Head and Neck Tumors / Parotid 01-22, 24 Flashcards

Question

An 80-year-old man presents with floor of mouth cancer on the right side. In addition to the 1-cm area of ulceration, there is a hard, warm, nonmobile, painful mass in the submandibular area. This mass most likely originated from which of the following types of tissue? ## Footnote A) Bone B) Fat C) Muscle D) Nerve E) Salivary

Answer 1

The correct response is Option E. The submandibular gland duct, also known as the Wharton duct, ends in the area of the floor of the mouth and is typically blocked when cancer invades this area. As a result, there is backup of salivary content, the gland enlarges, becomes firm and painful, and can even become infected. This event has no prognostic implications. However, an enlarged node, such as the perifacial nodes, can mimic this finding and can upstage a cancer patient. If a bimanual examination of the gland cannot be performed because of the patient's pain, a CT scan is easily confirmatory. In general, lymph nodes are mobile, with the rare exception of external bony erosion. Nonetheless, a complete head and neck physical examination can be key to interpreting the findings described. Bony expansion from a floor-of-mouth cancer is possible, but will not usually present as a painful mass. In general, fat is not involved. Nerve involvement can also occur, and perineural invasion in the lingual nerve can cause its enlargement, but not with this presentation. A sublingual infection or hematoma (e.g., Ludwig angina) can present with what is typically a swollen bilateral submandibular mass, as the infection/abscess extends below the mylohyoid muscle. This process can cause immediate airway compromise and many recommend an emergent tracheostomy. This pathology is almost always related to bacterial infections of the mouth, most commonly related to dental caries.

Answer 2

The correct response is Option D. Patients who undergo laryngopharyngectomy often have the thyroid gland removed as part of the operation. Sometimes, the parathyroid glands are removed accidentally or the blood supply is transiently interrupted, causing poor function. The parathyroid glands regulate calcium metabolism, and injury or removal of these glands manifests first as perioral tingling and numbness before more severe symptoms such as tetani. Hypernatremia is incorrect because, when symptomatic, it causes nausea, vomiting, and confusion. Hyponatremia is incorrect because, when symptomatic, it causes nausea, vomiting, lethargy, and confusion. Hypocalcemia is the correct answer because it is a concern for any patient who has this operation and reconstruction. Perioral tingling and numbness is an early sign of problems. Hypercalcemia is incorrect because, when symptomatic, it causes gastrointestinal issues such as vomiting, diarrhea, constipation, and skeletal muscle pain. Hyperkalemia is most likely to cause EKG changes and metabolism is not associated with parathyroid function.

Answer 3

The correct response is Option B. The findings on the panoramic x-ray study (Panorex) are most consistent with a dentigerous cyst, also referred to as a follicular cyst. These lesions are not tumors, but cysts that originate from the separation of the dental follicle from the crown of an unerupted tooth. Thus, dentigerous cysts arise during development and are odontogenic (from the tooth or its precursors) in origin. The cysts are lined by specialized epithelium that is instrumental in the formation of tooth enamel. This tissue usually atrophies and becomes part of the gingiva after the enamel is formed; a cyst forms when fluid accumulates between the atrophied or reduced enamel epithelium and the crown of an unerupted tooth. These cysts are most common around the mandibular third molar (wisdom tooth) and are seen most often in teenagers/young adults. They present as a painless bone expansion and appear on x-ray study as a well-circumscribed, unilocular radiolucency, often with a sclerotic rim. The relationship between the cyst and the tooth varies. Giant cell tumor, desmoid tumor, and osseous tumors associated with tuberous sclerosis are solid, not cystic lesions. The former two lesions tend to be more erosive on x-ray study and have a largely solid composition. Bony tumors arising in the context of tuberous sclerosis are uncommon, but tend to be solid. Cherubism is a rare autosomal dominant disorder that begins in childhood and in which mandibular and maxillary bone is replaced by fibrous tissue and cysts. It reportedly improves over time but can be disfiguring

Answer 4

The correct response is Option A. Post-transplant infections can be divided into three phases: early postoperative infections (0 to 2 months), intermediate (2 to 9 months), and late (greater than 9 months). Because of the variation in tissue type and anatomy between solid organ transplantation and composite tissue allograft transplantation, there are differences between types of infection. In all transplant patients, cytomegalovirus (CMV) infection/reactivation is the most common infectious complication. As a result, the protocol for composite tissue allograft recipients includes CMV prophylaxis. In this particular scenario, facial transplantation is unique in that there are oral and sinus cavities with colonization with native flora. Candida is the most ubiquitous and most common flora. Treatment is topical nystatin and clotrimazole. Although there is constant wariness for rejection, this does not occur commonly in the immediate postoperative period. Biopsy would be warranted if there is no improvement with topical antifungals. As there is no indication of acute rejection, increasing tacrolimus is not an appropriate initial treatment. Amoxicillin is a bactericidal antibiotic and is not an appropriate treatment for this fungal infection.

Answer 5

The correct response is Option A. Parotidectomy is a surgical procedure performed for benign and malignant tumors of the parotid gland and, uncommonly, for hypersalivation. Specific risks for parotidectomy include facial nerve injury, sialocele formation, and gustatory sweating. Gustatory sweating (or Frey syndrome) results when there is aberrant innervation of cutaneous sweat glands in the cheek skin overlying the parotid bed resulting in sweating and flushing during eating. Loss of taste to the anterior two thirds of the tongue results from injury to the chorda tympani, which arises from the facial nerve as it crosses the tympanic cavity and joins with the lingual nerve, not from injury to the facial nerve within the parotid gland. The stapedius is a small muscle in the middle ear that restricts movement of the stapes bone in response to loud noises. Hyperacusis may occur when the facial nerve is interrupted intracranially, before it exits the stylomastoid foramen and becomes extracranial. Tearing while eating (crocodile tear syndrome or Bogorad syndrome) is an uncommon consequence of nerve regeneration subsequent to Bell's palsy in which efferent fibers from the superior salivary nucleus become improperly connected to nerve axons projecting to the lacrimal glands causing tears while smelling foods or eating. Tardive dyskinesia is a disorder resulting in involuntary repetitive movements including grimacing, tongue and lip movements, and excessive blinking that usually occur as side effects of antipsychotic drugs. It is unrelated to facial nerve dysfunction.

Answer 6

The correct response is Option A. All phases of the Epstein-Barr virus life cycle are associated with human disease. In immunocompromised individuals, infected cells increase in number, and eventually B-cell growth control pathways are activated, inducing transformation and leading to malignancies such as nasopharyngeal carcinoma, Burkitt lymphoma, post-transplant lymphomas, and gastric carcinomas. Human papillomavirus (HPV) is increasingly recognized as a pathogenic risk factor for oropharyngeal cancer development. Accumulating molecular and epidemiological data now show that high-risk types of HPV are responsible for a subset of oropharyngeal cancer. Oral verrucous and squamous cell carcinomas have been reported in patients infected with hepatitis C virus, and the infection has been found to be more prevalent in patients with oral lichen planus. Infection with HIV is not known to be directly pathogenic in malignant transformation, but rather it increases the susceptibility to opportunistic infections and viral-promoted cancers. Human herpesvirus 8, also known as Kaposi sarcoma–associated herpesvirus, has been found in nearly all tumors in patients with Kaposi sarcoma.

Answer 7

The correct response is Option A. Any penetrating injury on a line from the tragus to the mid upper lip may injure the parotid duct or gland. The parotid system can be divided into 3 regions: Region A: gland Region B: duct superficial to the masseter muscle Region C: duct from the masseter to where it enters the mouth opposite the 2nd maxillary molar Additionally, the buccal branch of the facial nerve often runs with the duct. It can cross the superficial layer of the masseter after leaving the parotid gland. Injury manifests as weakness of the upper lip on animation. Injury not repaired acutely can manifest later as salivary fistulae or sialoceles. Most can be managed conservatively with drainage, pressure, and antisialagogues. Trying to find and repair the duct late after the injury is difficult and may not lead to resolution of the symptoms. This is usually reserved for early injury and repair. If these fail, then a superficial parotidectomy can be considered for recalcitrant salivary collections.

Answer 8

The correct response is Option A. The area of the lips, gums, teeth, tongue, and anterior hard palate will drain to the submental and submandibular region (Level I). Levels IA (submental) and IB (submandibular) are separated by the anterior digastric muscle. Group II drains the naso-/oro-/hypopharynx and parotid and is called the upper jugular group. Group III ( middle jugular group) drains the naso-/oro-/hypopharynx and larynx. The lower jugular group (level IV) drains the larynx, cervical esophagus, and hypopharynx. Group V is the posterior triangle group and drains the naso- and oropharynx. Group VI is the anterior central group below the hyoid and above the sternal notch. The group drains the thyroid, parathyroid, cervical esophagus, and larynx. More posteriorly the hard palate and soft palate will drain to the retropharyngeal space and deep cervical nodes.

Answer 9

The correct response is Option A. One of the branches of the facial artery is the submental artery. This vessel provides flow to the so-called submental flap, which can be made myofascial or musculocutaneous as it includes the platysma muscle. The flap is almost adjacent to the defect and provides similar skin in color and texture. The donor site is typically closed primarily after undermining the lower neck. The thoracoacromial artery provides flow to the pectoralis flap. Although the pectoralis myocutaneous flap could be used here, it would be bulky, would have to exclude breast tissue, would not have a similar color match, and would create a tether from the chest to the chin. The superficial temporal artery can allow for a large laterally based forehead flap; in the era prior to free tissue transfer, this flap was used for even intraoral reconstruction. In theory, such a flap could reach the mental area, but the dissection would be very tedious and the donor site alterations significant. The transverse cervical artery can provide a flap of thin supraclavicular skin that, as a free flap, could be used in this area but certainly would not be the simplest option. Likewise the radial forearm free flap based on the radial vessels would not be a good color match and would be a lengthy, complex surgery.

Answer 10

The correct response is Option E. Selective removal of nodes in levels I to III is the procedure of choice for N0 and N1 cancers in the oral cavity. Lateral and anterior compartment dissections miss Level I, which is the closest lymphatic level to a base of tongue cancer. Modified neck dissections are indicated for clinically palpable metastatic disease. Radical neck dissections are indicated for involvement of the nerve, vein, or muscle.

Answer 11

The correct response is Option E. There are many choices for bone grafts, both vascularized and nonvascularized. In this clinical scenario, there is no question that a vascularized bone graft is indicated, given the irradiated field, anterior location, and \>6-cm defect. The choice of vascularized bone grafts include the free fibula, free iliac crest, free scapula, and free radius bone grafts. All have their pros and cons individually, although collectively, vascularized bone free flaps provide 40% more strength, 56% more stiffness, higher complete arthrodesis rate, and superior functional outcomes. The free fibula flap would be the most common choice for this situation given its long pedicle (6 to 10 cm), the large amount of usable bone (22 to 24 cm), minimal donor site morbidity, ability to accept dental implants, and reliable skin flap (skin island survival rates approaching 100% due to increased anatomical understanding and improvements in harvest techniques). However, its disadvantage is that it doesn’t have the vertical height of the free iliac crest.

Answer 12

The correct response is Option C. Hyperlacrimation, or Bogorad syndrome, is a known complication after Bell palsy or other injury and insults to the facial nerve. Similar to Frey syndrome, the predominant theory for this form of gustatory hyperlacrimation is due to aberrant facial nerve regeneration. Epiphora in general can also occur due to poor “pumping mechanisms” in the eyelids as well as prolonged ectropion and conjunctival show after facial nerve injury. However, hyperlacrimation during gustatory activity is a specific and definable pathology. Treatment for this syndrome includes subtotal lacrimal gland resection, botulinum toxin type A, and various forms of enlarging the lacrimal tract. Synkinesis is a common event after facial nerve regeneration, when the nerve improperly fires and there is lack of typical mimetic muscle coordination. The anterior portion of the tongue taste buds are innervated by facial nerve fibers from the chorda tympani to the lingual nerve, but the base of the tongue is innervated by cranial nerves IX and X. Anosmia is loss of smell that occurs through cranial nerve I injury or obstruction and can lead to taste disturbances. Migraine headaches can be associated with a variety of syndromes and need to be differentiated from other forms of headaches. Ramsay Hunt syndrome can lead to facial nerve dysfunction and facial pain, but this pain is not associated with facial nerve regeneration or migraine headaches.

Answer 13

The correct response is Option A. This radiograph is most consistent with a dentigerous cyst. Dentigerous cysts are the second most common and develop in the dental follicle of an unerupted tooth. On radiograph there is usually a lucency attached at an acute angle to the tooth. The mandibular and maxillary third molars are the most commonly affected. Odontogenic cysts are epithelial lined cysts that are defined by location and histologic characteristics. Periapical cysts are the most common and usually form from necrotic pulp after a tooth infection. They usually present as a radiologic lucency at the apex of the tooth. A gingival cyst is a superficial cyst in the gingiva. A primordial cyst develops instead of a tooth. This is a rare cyst. A residual cyst may result from a retained periapical cyst after teeth have been removed.

Answer 14

The correct response is Option A. When a facial nerve has been divided or resected, the best outcomes for regaining function are usually obtained from direct repair, or cable nerve grafting when too great a distance for direct repair separates the nerve ends. While autologous nerve grafts from “expendable” donor nerves, such as the great auricular nerve or sural nerve, have long been the gold standard, nerve repair using biologic or synthetic nerve conduits has also produced reasonable results, in some series equivalent to cable nerve grafts. Conduit nerve repair has the advantage of having no donor site morbidity. However, the length of the gap between the proximal and distal cut nerve ends is usually limited to less than 3 cm for the best chances of nerve recovery. When direct repair or cable nerve grafting is not possible—for example, when the nerve has been resected very proximally up to the intracranial portion of the nerve—cross-facial nerve grafting between redundant branches of the normal contralateral nerve and the distal facial nerve stumps of the paralyzed side can produce reasonable results with spontaneous symmetrical facial movement. Performing a nerve transfer from a donor nerve, such as the masseteric (V), spinal accessory (XI), or hypoglossal (XII) nerve can provide facial tone and symmetry at rest, and, in some cases, volitional movement with training. A temporary nerve transfer to these nerves is sometimes performed as a “babysitter” procedure while awaiting axonal growth through cross-facial nerve grafts. When nerve repair or nerve transfers from the contralateral face or donor nerves are not feasible, such as after motor endplate degeneration has occurred in the facial muscles, innervated free muscle flap transfers can restore facial movement to the lower face. Muscles commonly used for facial reanimation include the gracilis, pectoralis minor, serratus anterior, and latissimus dorsi, because of their thinness, good excursion, and low donor site morbidity. In addition to a microvascular anastomosis, an epineural nerve repair is performed either to a cross-facial nerve graft or to a donor cranial nerve such as the masseteric nerve.

Answer 15

A 45-year-old man is evaluated because of a 5-cm mass at the angle of the mandible. A CT scan shows an intraparotid mass. Ultrasound-guided fine-needle aspiration shows benign findings. Which of the following is the most appropriate next step in management? ## Footnote A) Chemotherapy and superficial parotidectomy B) Follow-up evaluation in 3 months C) MRI D) Superficial parotidectomy only E) Total parotidectomy

Answer 16

The correct response is Option B. Although minor salivary gland tumors are much less common than major salivary gland tumors, minor salivary gland tumors are much more likely to be malignant. Additionally, pediatric salivary cancers represent only about 5% of all salivary cancers, but are also more likely to be malignant (almost 50% were malignant in Armed Forces Institute of Pathology series of 168 pediatric salivary gland tumors). Finally, the palate is the most common source of minor salivary gland tumors, which are more likely to be malignant and higher stage when detected. The clinical presentation of paresthesias of adenoid cystic carcinoma (ACC) suggests perineural invasion. One series (University of Maryland) of 243 minor salivary gland tumors found 78% of them were malignant, and of those malignant tumors, 15% were ACC. Given the perineural invasion symptoms, imaging, in particular MRI, can detect perineural invasion and help plan the degree of surgery. In this scenario, clinical exam pointed to perineural invasion, which should be imaged to plan for surgery. Chemotherapy is not used in the treatment of this disease. Radiation therapy alone is not usually performed, as this is considered a surgical disease. However, it can be used as adjuvant therapy in addition to surgery. Excisional biopsy usually recommends 1- to 2-cm margins. Patients with high-stage, perineural invasion, lymphadenopathy, or other signs of extensive disease may receive surgery with adjuvant radiation therapy. Regardless, ordering a CT scan and MRI is a reasonable initial approach before surgical treatment.

Answer 17

The correct response is Option B. Most patients who undergo hemiglossectomy can expect reasonable speech and swallowing function when reconstructed with a thin, pliable free flap, such as the radial forearm fasciocutaneous free flap, that facilitates unrestricted residual tongue movement. Although his swallowing may likely improve as he recovers from surgery and tissue edema resolves, this patient will need a feeding tube to maintain his nutrition at this time. Additionally, it can be difficult for many patients who have undergone substantial tongue resections to meet their caloric needs even if they pass their initial swallowing study during radiation therapy and short-term feeding tube placement may be indicated. Tracheoesophageal puncture with placement of a one-way valve speech prosthesis is used to restore speech function in patients who have received a laryngectomy and does not apply to this patient. Revision of the free flap is not indicated in the early postoperative period as it is unlikely to significantly improve swallowing and may delay adjuvant treatment. A laryngectomy for aspiration would only be indicated as a last resort in a patient with chronic, long-term aspiration of oral secretions resulting in recurrent pneumonia, most commonly following more extensive tongue resections, such as a total glossectomy, including removal of the tongue base. Postoperative radiation therapy should be administered within 4 to 6 weeks of surgery for maximal effectiveness and, therefore, delaying for 10 more weeks may adversely affect this patient's survival.

Answer 18

The correct response is Option D. Frey syndrome occurs with injury and abnormal regeneration of the auriculotemporal nerve, but is a late complication (median time at presentation: 11 months). Postoperative facial nerve dysfunction can occur in up to 60% of patients, but the majority (90%) resolve without need for operative intervention. Tinnitus is not a recognized complication of superficial parotidectomy, and hematoma is an early complication (\<24 hours). Patients with sialadenitis alone have increased risk for developing salivary fistulae.

Answer 19

The correct response is Option D. Direct closure is being used more commonly in large Mohs facial defects, especially in the elderly, as it minimizes the disruption of skin tension lines. The contraindication in this case to closure alone is the nodal involvement and the extension into the parotid capsule. Given the parotid capsule extension, adequate margins at a minimum will require a superficial parotidectomy. Radiation alone plus flap closure would have a higher recurrence rate because residual disease is left in the capsule. The nodal enlargement requires further evaluation and given the options the best combination is superficial parotidectomy, neck dissection, and a local rotation flap.

Answer 20

The correct response is Option E. Salivary gland tumors are relatively rare and make up about 3 to 4% of all head and neck neoplasms. The majority of salivary gland tumors (approximately 80%) originate in the parotid gland. Approximately 80% of parotid gland tumors are benign. Facial paralysis may be associated with malignant tumors and are a sign of neural invasion. Warthin tumor (papillary cystadenoma lymphomatosum) is the second most common tumor of the parotid gland and is benign. Warthin tumors predominantly occur in men of 50 to 70 years of age, most frequently smokers, and are the most common bilateral salivary gland tumors. The histologic appearance of this tumor is very characteristic and is characterized by papillary cysts and mucoid fluid as well as nodules of lymphoid tissue. Pleomorphic adenoma, also known as benign mixed tumor, is the most common tumor of the parotid gland. This tumor is histologically characterized by epithelial and connective tissue elements, with stellate and spindle cells interspersed within a myxoid background. Adenoid cystic carcinoma is the second-most common malignancy of the salivary glands after mucoepidermoid carcinoma and exhibits a propensity for perineural invasion. There are three histologic subtypes: cribriform, tubular, and solid. The cribriform pattern has a classic “swiss cheese” appearance with cells arranged in nests separated by round or oval spaces. The tubular pattern has a glandular architecture, while the solid (or basaloid) pattern has sheets of cells with little or no luminal spaces. Hemangiomas are the most common salivary gland tumors found in children and usually involve the parotid gland. Histologically, the tumors are composed of capillaries lined by proliferative endothelial cells. Squamous cell carcinoma is a malignant tumor that rarely involves the parotid gland, in comparison to the skin and aerodigestive tract. It is histologically identical to squamous cell cancers arising from other sites with epithelial cells that form sheets or compact masses, which invade adjacent connective tissue. Round nodules of keratinized squamous cells known as “keratinous pearls” are the hallmark of well-differentiated squamous cell carcinoma.

Answer 21

The correct response is Option A. Bisphosphonate-related osteonecrosis of the jaw is a condition found in patients who have received intravenous and oral forms of bisphosphonate therapy for various bone-related conditions such as osteoporosis. The patient may develop exposed, nonvital bone involving the maxillofacial structures. Osteonecrosis may occur following minor trauma with decreased capacity for bone healing due to the effects of bisphosphonate therapy. Treatment may involve antimicrobial rinses, systemic antibiotics, systemic or topical antifungals, and discontinuation of bisphosphonate therapy. Raloxifene is in a class of drugs called estrogen agonists/antagonists that have been developed to provide the beneficial effects of estrogens without their potential disadvantages. It is neither an estrogen nor a hormone. Raloxifene used to be called a selective estrogen receptor modulator (SERM). Calcitonin is a synthetic hormone for the treatment of osteoporosis. The naturally occurring hormone is involved in calcium regulation and bone metabolism. Teriparatide, a type of parathyroid hormone, is approved for the treatment of osteoporosis in postmenopausal women and in men who are at high risk for fracture. Estrogen therapy with or without progesterone is approved for the prevention of osteoporosis in postmenopausal women. Estrogen reduces bone loss, increases bone density in both the spine and hip, and reduces the risk for hip, spine, and other fractures in postmenopausal women.

Answer 22

The correct response is Option B. When dental implants are placed in thicker cortical bone, better initial stability is achieved at the bone implant interface, reducing micromotion during the process of osseointegration. Cortical bone thickness has also been shown to correlate with the amount of torque required to remove a dental implant. No significant correlation has been shown between removal torque and total bone thickness. The presence of osteogenic cells in cancellous bone is responsible for a biologic response, although it is not as important in improving initial stability as thick cortical bone. Periosteal thickness is not relevant to dental restoration.

Answer 23

The correct response is Option A. The submental flap is a potentially thin flap. Its pedicle is the submental artery, which arises off the facial artery. The pedicle is described as traveling between the submandibular gland and digastric muscle belly. It also dives deep and lies in between the mylohyoid and geniohyoid. Exposing the pedicle requires incision along the mental region, then in a transverse incision 1 to 2 cm below the mandibular body. Level I nodes lie within the submental region with the mandibular body being the superior border and the hyoid bone being the inferior margin. They are further divided into 1a-submental, which lies anterior to the anterior belly of the digastric, and the 1b-submandibular, which lies posterior to the anterior belly of the digastric. Thus, exposure to the pedicle alone also exposes all the level I nodes. Level II nodes are the upper jugular group, which are clustered around the upper third of the internal jugular vein. The superior border is the skull base, the hyoid is the inferior border, the anterior border is the anterior edge of the sternocleidomastoid, and the posterior edge is the posterior edge of the sternocleidomastoid. Level III nodes are the middle third of the internal jugular, with the hyoid being the superior border, cricoid cartilage the inferior border, and the anterior posterior borders the anterior and posterior edges of the sternocleidomastoid, respectively. Level IV nodes are the lower third of the internal jugular with the cricoid cartilage as the superior border and the clavicle as the inferior border. Again, the anterior border is the anterior edge of the sternocleidomastoid, and the posterior edge is the posterior edge of the sternocleidomastoid.

Answer 24

The correct response is Option B. Reconstructive strategies for partial and hemiglossectomy reconstruction are different than for subtotal and total glossectomy reconstruction. For partial and hemiglossectomies, the ideal reconstruction preserves the mobility of the remaining tongue, maintaining its ability to manipulate foods, articulate words, and sweep the oral cavity clean. Such defects are best reconstructed with a thin, pliable flap that resists contraction during the healing process. Of the choices listed, the radial forearm fasciocutaneous free flap best fits those requirements. The pectoralis major myocutaneous pedicled flap is usually too thick to permit ideal movement and can have problems with reach and tethering to the chest as the proximal flap and pedicle contact during healing. The temporalis muscle pedicled flap is unlikely to reach the entire defect and the muscle is likely to contract and stiffen with time, limiting tongue movement. The rectus abdominis myocutaneous free flap is usually too thick to permit unrestricted movement of the remaining hemitongue and is better suited to subtotal and total glossectomy reconstruction, which is best effected with a bulky flap that diverts food and liquids laterally into the pharynx rather than into the larynx. A split-thickness skin graft, while thin, usually contracts substantially, limiting tongue movement. Also, if there is communication into the neck following tongue resection with neck dissection, the skin graft would be at high risk for resulting in a fistula.

Answer 25

The correct response is Option D. A 2-cm mass with a clinically negative neck, pT2cN0, merits a supraomohyoid neck dissection because of the high risk of occult spread in this zone. A supraomohyoid dissection removes the lymph nodes in zones I, II, III; a modified neck dissection covers I-IV. A smaller tumor, pT1N0, can be managed with a "tight 'wait and watch'" strategy. A radical neck dissection includes the sternocleidomastoid muscle and is not necessary for a clinically negative neck. Adding radiation therapy to a reflex neurovascular dystrophy is also not necessary for an N0 neck.

Answer 26

The correct response is Option B. The most common benign tumors of the jaw are ameloblastoma (37%) and keratocystic odontogenic tumor (KCOT) (14%). Ameloblastomas are slow growing, occur in the 4th to 5th decades of life, and arise from odontogenic epithelium. KCOTs are locally aggressive, occur earlier in life, and also arise from odontogenic epithelium. Curettage or enucleation results in higher recurrence rates. Addition of Carnoy's solution (absolute alcohol, chloroform, glacial acetic acid, and ferric chloride) to the enucleated site for 3 minutes addresses the most common issue of local recurrence. Segmental or marginal resection of the mandible is reserved for recurrence after resection locally.

Answer 27

The correct response is Option C. Bilateral expansile lesions of the inferior alveolar nerve canal is pathognomonic of neurofibroma. The lesions on the Panorex are both expansile and not locally destructive of bone, as is common in ameloblastoma and odontogenic keratocysts. Central giant granulomas are most often multilocular, with cortical rupture and root atrophy. Osteosarcoma always has cortical destruction.

Answer 28

The correct response is Option D. It is important to note that any patient experiencing pain like this should be worked up for recurrent disease. Nevertheless, this question addresses two issues in head and neck reconstruction. First, most non-oral cavity head and neck cancers are now treated primarily with chemoradiation protocols. This leaves surgery for salvage or for dealing with the morbidities of the therapy. In this case, the patient is now experiencing bilateral osteoradionecrosis with a pathologic fracture on the right. Had this problem stopped with the left side, debridement and letting the mandible sway to the ipsilateral side would be a form of management, although it can be disfiguring. Secondly, from a reconstructive standpoint, this is a challenging case; but advances in flaps and preoperative modeling allow for managing such situations in one procedure. Given how long the fibular free flap can be fashioned and the ability to remove large central pieces of bone, surgeons can create two osseous segments vascularized off the same pedicle. Since many of these patients have difficult necks from a recipient vessel standpoint, decreasing the number of needed anastomoses is beneficial. Two free flaps can be performed at the same time or sequentially, but this adds increasing morbidity and complexity to the situation. In this case, a single fibular free flap with plates designed using stereolithographic modeling was adequate to restore the patient’s ability to eat and articulate. It also improved his occlusion, and, with debridement, stopped his pain. Postreconstructive imaging is shown. Now that the right side is involved, simple debridement only would leave the patient potentially an oral cripple. By definition, the bone is of poor quality and simple open reduction and internal fixation will not restore the patient's function or promote proper healing. Hyperbaric oxygen is used for osteoradionecrosis, but numerous studies now question its benefit in craniofacial bone, and it would not address the pathologic fracture on the right. Hyperbaric oxygen was shown to positively influence the osteoradionecrotic tissues prior to and post-free tissue reconstruction. Finally, a free bone graft in this situation, even with additional soft tissue coverage, would not address the major issue of hypoperfusion to the affected bone.

Answer 29

The correct response is Option D. Oral cavity cancers are staged based on the following criteria set forth by the American Joint Committee on Cancer (AJCC): The cancer described in the scenario is a stage T2N0M0 cancer of the lip. Surgical excision with margin control is the most appropriate and probably the most common treatment for this lesion, although Mohs micrographic surgery may also be an option for surgical removal. Reconstruction would be performed after attaining adequate surgical margins and can be performed utilizing local tissue flaps in most patients. 5-Fluorouracil cream can be used in the treatment of actinic keratosis and superficial basal cell cancers. It is also used in the treatment of some squamous cell cancers, but its efficacy is lower and would not be indicated for a T2 cancer. In curettage and electrodessication, small tumors are scraped off with a curette and electrocautery destroys residual tumor and controls bleeding. It is used for superficial squamous cell cancers without high-risk characteristics in noncosmetically sensitive sites and would not be appropriate for this lesion. Also, surgical margins cannot be evaluated with this technique. Photodynamic therapy involves application of a photosensitizing agent, such as 5-aminolevulinic acid (5-ALA), that is taken up by the cancer cells. The next day, the medicated areas are activated by a strong light. The treatment selectively destroys cancer cells while causing minimal damage to the surrounding tissue. It is used to treat actinic keratosis and is not approved by the Food and Drug Administration for treatment of squamous cell carcinoma, although experience suggests that it is effective for small, superficial cancers. Radiation therapy alone can be used in cosmetically and functionally important sites such as the lip or in patients who are poor candidates for surgery because of medial comorbidities. Given the good functional and cosmetic prognosis of surgical resection and reconstruction in this patient, irradiation would likely be reserved for a recurrent cancer. Combined surgery and irradiation is usually reserved for T4-stage cancers or those with nodal metastases.

Answer 30

The correct response is Option B. The finding of a negative vector places the patient at an elevated risk for lower lid malposition and ectropion. The negative vector refers to the anatomic relationship on lateral view of the maximum projecting point of the globe and the maximum projecting point of the infraorbital malar prominence. If the globe projects less than the malar prominence, a negative vector exists. Conversely, if the malar prominence projects more than the globe, a positive vector exists. The negative vector finding indicates potentially deficient globe and lid support based on skeletal anatomy. Such patients will often have minor scleral show or lateral lid lag. It is important to recognize these findings prior to blepharoplasty surgery in order to surgically address the risks of ectropion via primary lid suspension during the blepharoplasty. Occasionally, lower lid blepharoplasty may be avoided if a negative vector is present and other conditions such as dry eye exist. Other findings or conditions that are associated with postoperative ectropion and lower lid malposition are: orbicular weakness, anterior lamellar shortage, inferior eyelid/orbital volume deficit, and eyelid laxity. Excessive or prominent middle lamellar scarring can occur after surgery, which can also lead to lid malposition. Lagophthalmos is the inability to lower the upper lid fully and is a negative consequence of upper blepharoplasty due to excessive tissue resection or fibrosis. Enophthalmos is interior retraction or displacement of the globe related to increased orbital volume. This is unrelated to lower blepharoplasty surgery. Proptosis is an external displacement of the globe giving the appearance that the eyeball is extruding from the obit. This is most often associated with Graves disease, head trauma, and increased intracranial pressure. It can also be due to a retrobulbar hematoma after blepharoplasty, which is a surgical emergency due to the risk of blindness. Dystopia refers to malposition of the globe related to skeletal changes of the orbit. This would not be a result of blepharoplasty, but can occur after facial trauma or facial tumor resection.

Answer 31

The correct response is Option E. This patient has T2N1M0 (Stage II) high-grade mucoepidermoid carcinoma, and total parotidectomy with ipsilateral cervical dissection is the appropriate treatment. Because the patient is lymph node positive, both an ipsilateral cervical lymph node dissection and postoperative adjuvant radiotherapy are indicated. A superficial parotidectomy would perhaps be indicated in a low-grade mucoepidermoid carcinoma, but in a high grade lesion, total parotidectomy is more appropriate. Ipsilateral cervical lymph node dissection and postoperative adjuvant radiotherapy would be indicated in this patient, however. Although total parotidectomy and ipsilateral cervical lymph node dissection are appropriate, two factors make postoperative adjuvant radiotherapy an important component of treatment: the node positive status of the neck, and the high grade of the tumor. Chemotherapy remains somewhat controversial in the treatment of mucoepidermoid carcinoma, and, to date, is not a part of standardized therapy.

Answer 32

The correct response is Option C. This patient has a bilateral maxillectomy defect following resection via a Le Fort I osteotomy. While small defects can be successfully addressed with prosthetic palatal obturators that fit through the wound margins and clasp to the remaining teeth, larger defects can rarely be obturated because of their weight and instability due to lack of dentition and an alveolar ridge. Bone grafting is also not an option for such a large defect, particularly one resulting from a malignancy where postoperative radiation therapy is likely. In general, bone grafts are only indicated in benign conditions with bone loss less than 5 cm in length. Even when these conditions are met, they require coverage with well-vascularized tissue. Temporalis muscle flaps can be used to reconstruct palatal defects, but in this case, the skeletal elements of the mid face have been removed. Temporalis muscle flaps alone will result in loss of mid face projection. Similarly, the anterolateral thigh free and rectus abdominis myocutaneous free flaps are frequently used to reconstruct posterior maxillary defects but, though bulkier than temporalis muscle flaps, will not maintain midfacial projection in this patient with loss of the entire palate and premaxilla. The most appropriate reconstruction for this patient is the fibula osteocutaneous free flap. This flap will restore midfacial height, width, and projection. It has adequate bone stock for osseointegrated implant placement dental restoration as well. The skin paddle is used to close the palatal defect, separating the oral cavity from the nasal cavity. Several other osteocutaneous free flaps, including the iliac crest and scapular osteocutaneous free flaps, have also been used for similar reconstructions.

Answer 33

The correct response is Option A. The circumflex scapular artery, which is a branch of the subscapular artery, supplies blood to the lateral and medial borders of the scapular bone. The scapula free flap was first described in 1978 by Saijo. It can be harvested as part of a chimeric flap that includes other tissues supplied by the subscapular arterial system, such as the latissimus dorsi muscle, serratus anterior muscle, and scapular or parascapular skin. The tip of the scapula receives its blood supply from the angular branch of the thoracodorsal artery and has also been utilized as a pedicle for the inferior portion of the scapula. While the scapular bone is not as thick as the fibula bone, it provides adequate stability for mandibular reconstruction. Cutaneous branches of the circumflex scapular artery supply the scapular and parascapular skin and, therefore, a skin flap can be harvested simultaneously to close soft-tissue defects. The transverse cervical artery and the dorsal scapular artery primarily supply the trapezius muscle and overlying skin. The thoracoacromial artery supplies the pectoralis major muscle and overlying skin. The lateral thoracic artery supplies both the lateral portion of the pectoralis major muscle and the skin in the axillary region.

Answer 34

The correct response is Option C. The patient described has an ameloblastoma. Ameloblastomas are benign tumors of odontogenic origin. Treatment is surgical. Conservative management, such as local curettage, is associated with high recurrence rate. The most appropriate treatment is segmental mandibulectomy, reconstruction, and dental rehabilitation. Because ameloblastoma is benign, neither adjuvant therapy nor neoadjuvant therapy is indicated.

Answer 35

The correct response is Option A. In the patient described, with a history of previous radiation therapy and a full-thickness defect, a free latissimus dorsi musculocutaneous flap would be the best choice for soft-tissue reconstruction. Skin grafting over an implant cranioplasty would not be a suitable option in this setting. Skin grafts could be considered in nonradiated, partial-thickness defects of the scalp or for coverage of scalp rotation flap donor sites. A pedicled trapezius musculocutaneous flap would not reach the cranial vertex without undue tension and is better suited for full-thickness occipital defects. Scalp rotation flaps are ideal for defects up to 8 cm in diameter in a nonradiated scalp. The patient’s history of previous radiation therapy would likely compromise the viability of a large rotation flap in this setting. Negative pressure wound therapy over an implant cranioplasty in a radiated field would not allow for soft-tissue healing and coverage.

Answer 36

The correct response is Option C. The most appropriate method for wound closure is a radial forearm free flap, as it matches the thin skin and subcutaneous tissue of the temporal area and has a long pedicle that can reach recipient vessels in the neck. With a patient history of radiation therapy and superficial parotidectomy, the superficial temporal vessels are unlikely to be suitable recipient vessels. With a patient history of upper neck dissection, it is possible that suitable recipient vessels will only be found inferiorly, and thus, it is best to use a flap with a long, reliable pedicle. A split-thickness skin graft will likely fail in a radiated wound bed. A scalp rotation flap will likely include tissue in the radiation field, bring hair-bearing tissue into a non–hair-bearing area, and require a split-thickness skin graft for closure of the donor site. It could be considered in a patient who is not a candidate for free tissue transfer. The lateral arm flap and parascapular flap are slightly thicker than the radial forearm flap, but the principal reason to avoid these flaps in this patient is that their pedicle lengths are relatively short and may not reach the recipient vessels in the neck.

Answer 37

The correct response is Option E. Oral cavity cancers are staged based on the following criteria set forth by the American Joint Committee on Cancer: Primary tumor staging for oral cavity cancers (T) TXPrimary tumor cannot be assessed T0No evidence of primary tumor TisCarcinoma in situ T1Tumor = 2 cm in greatest dimension T2Tumor \>2 cm but not more than 4 cm in greatest dimension T3Tumor \>4 cm in greatest dimension T4aModerately advanced, local disease Lip – Tumor invades through cortical bone, inferior alveolar nerve, floor of mouth, or skin of face Oral cavity – Tumor invades adjacent structures (e.g., through cortical bone, into deep extrinsic muscle of the tongue, maxillary sinus, or skin of face) T4bVery advanced, local disease Tumor invades masticator space, pterygoid plates, or skull base and/or encases internal carotid artery The cancer described is a stage T4aN0M0 cancer of the floor of mouth. The T-stage is 4a based on cortical mandibular invasion demonstrated by radiographic imaging. Concern for mandibular invasion should be raised whenever a tumor abuts or is fixed to the mandible. Mandibulectomy is indicated. Cortical invasion of the mandible is an indication for segmental mandibulectomy, in which the full thickness of the involved mandible and grossly disease-free margin are removed by osteotomies. Marginal mandibulectomy involves removal of the alveolar ridge and varying amounts of the inner or lingual table of the mandible depending on the location of the tumor. Marginal mandibulectomy is performed when cancers abut the mandible or invade the periosteum, but do not grossly invade the cortex of the bone. Although clinically and radiographically the neck does not have nodal metastases (stage N0), surgical treatment is usually performed due to the risk for occult nodal metastases (20% or more in some studies). Such dissection also facilitates reconstruction by exposing potential recipient blood vessels for microvascular free tissue transfer.

Answer 38

The correct response is Option E. Ameloblastomas are benign odontogenic tumors derived from odontogenic epithelium. They are typically slow growing, and present in the fourth or fifth decade of life as a mandibular mass in most individuals (80%). Odontogenic cementoblast tissue is not appropriate because this tissue gives rise to an extremely rare benign odontogenic tumor, the cementoma. Gingiva is the mucosal covering of the alveolar bone. Enamel is the dense compound of teeth.

Answer 39

The correct response is Option A. Osteoradionecrosis (ORN) of the mandible is uncommon but can occur in up to 10% of patients after undergoing radiation therapy for oral cancers. The risk increases once radiation doses exceed 6500 cGy. Most reports of ORN have dental caries and extraction sites as precipitating factors. Periodontal disease can also lead to ORN. After undergoing radiation therapy, patients can develop oral candidiasis and xerostomia, and they may also have edentulous mandibles with dental implants after reconstruction. However, these do not increase the risk for ORN. Surgical resection and hyperbaric oxygen therapy are the mainstays of treatment.

Answer 40

The correct response is Option B. The circumferential defect described in this patient requires coverage with a tubularized flap that can span the length of the defect and reestablish continuity of the alimentary track. Gastric pull-up is not a good option in this case because of its high morbidity and poor perfusion in the most proximal region of the gastric flap. Coverage with the pectoralis flap or deltopectoral flap is not an appropriate option because these flaps cannot be tubularized in a single-stage reconstruction. The spit fistula would not restore alimentary tract continuity, and it should only be used if no other reconstructive options are available or if the patient is medically unstable. The anterolateral thigh flap is the best option in this case because it can be tubularized to span the defect. In most cases, the resulting reconstruction is highly effective with restoration of swallowing function in the majority of patients.

Answer 41

The correct response is Option B. Salivary gland tumors are relatively rare and make up about 3 to 4% of all head and neck neoplasms. Approximately 80% of salivary gland tumors originate in the parotid gland. Approximately 80% of parotid gland tumors are benign. Facial paralysis may be associated with malignant tumors and is a sign of neural invasion. Malignant tumors may also metastasize to the regional lymph nodes and to distant sites. Mucoepidermoid carcinoma is the most common malignancy of the parotid gland and the second most common malignancy of the submandibular and minor salivary glands. Mucoepidermoid carcinomas contain two major elements: mucus-secreting cells, and epithelial cells of the epidermoid variety. Low-grade tumors are associated with a predominance of mucus-secreting cells lining cysts and intervening nests of well-differentiated epidermoid cells. High-grade tumors show few or no mucus-secreting cells and the epidermoid cells are poorly differentiated. Intermediate-grade tumors are defined by less cyst formation than low-grade tumors with nests of epidermoid and less differentiated intermediate cells. The biologic behavior of mucoepidermoid carcinomas correlates with their histologic grade. On the basis of the nerve invasion, the appropriate treatment for this patient includes radical parotidectomy with facial nerve sacrifice. A neck dissection should also be performed for high-grade lesions or those with suspicious adenopathy. Postoperative radiation therapy is usually recommended for higher-grade mucoepidermoid cancers. Pleomorphic adenoma, also known as benign mixed tumor, is the most common benign tumor of the parotid gland. This tumor is histologically characterized by epithelial and connective tissue elements, with stellate and spindle cells interspersed with a myxoid background. Warthin tumor (papillary cystadenoma lymphomatosum) is the next most common tumor of the parotid gland and is also benign. Warthin tumors predominantly occur in males and are bilateral in 10% of patients. Histologically, they are characterized by papillary cysts and mucoid fluid as well as nodules of lymphoid tissue. Hemangiomas are the most common salivary gland tumors found in children, and usually involve the parotid gland. Like other hemangiomas, they are benign and characterized by a rapid growth phase around the age of 1 to 6 months, followed by gradual involution over 1 to 12 years. Histologically, the tumors are composed of capillaries lined by proliferative endothelial cells. Squamous cell carcinoma is a malignant tumor that rarely involves the parotid gland, in comparison with the skin and aerodigestive tract. When squamous cell cancers occur in the parotid gland, they are usually of metastatic origin, although primary squamous cancers of the salivary glands do occur. They are histologically identical to squamous cell cancers arising from other sites with epithelial cells that form sheets or compact masses that invade adjacent connective tissue. Round nodules of keratinized squamous cells, known as “keratinous pearls,” are the hallmark of well-differentiated squamous cell carcinoma.

Answer 42

The correct response is Option A. The fibula flap is the most appropriate option in this case because a long section of bone requiring multiple osteotomies is needed. The fibula flap can provide 18 to 20 cm of bone and has both an endosteal and periosteal blood supply enabling shaping of the bone with multiple osteotomies. In addition, a skin paddle can be harvested with the flap to reconstruct the floor of mouth defect. The scapula and radial forearm flaps also provide bone and soft tissues; however, these flaps will not provide a long enough bone segment and cannot be reliably osteotomized in multiple locations. The rectus and pectoralis flaps are soft-tissue flaps, and their use in this case would result in marked deformity because the anterior arch has been resected.

Answer 43

The correct response is Option B. The anterior tonsillar pillar (palatoglossal arch) and tonsil are the most common site for primary neoplasms of the oropharynx. A 1-cm tumor (T1) at this location has a 71% incidence of cervical lymph node metastases. Oropharyngeal tumors arising at the base of the tongue have a similar incidence of lymphatic metastases, whereas oropharyngeal wall and soft palate T1 tumors only metastasize in 8 to 25% of cases. The most direct path of lymphatic drainage from the oropharynx is to level II (jugulodigastric) lymph nodes, which can be examined clinically. From level II the progression is sequential to levels III, IV, and V. It is rare to encounter a “skipped” level. The other less frequent lymphatic drainage pathways detectable only on imaging studies are to retropharyngeal and parapharyngeal nodes. Midline tumors can drain to bilateral lymphatic systems.

Answer 44

The correct response is Option C. Palatal obturators can adequately restore missing maxillary dentition as well as prevent oronasal leakage of air, liquids, and foods. They have the advantage of being removable, which permits visualization of the maxillary cavity for tumor surveillance. Prosthetic retention can be difficult or impossible in sizable defects, particularly when there are few teeth to stabilize the prosthesis. In this patient who has sufficient remaining maxillary teeth and the majority of the alveolar arch, the prosthesis is expected to have good stability, and would be the appropriate choice in a patient who wishes to avoid further invasive procedures. The temporalis muscle flap can be transposed into the oral cavity and can be used for closing defects of the palate. However, this flap alone would not provide replacement of the missing dentition and is still more invasive than a palatal obturator. Additionally, the temporalis muscle flap results in marked temporal hollowing at the donor site. The rectus abdominis musculocutaneous free flap can close the palatal defect and restore shape to the cheek in patients with a unilateral maxillectomy. In combination with a dental prosthesis, the rectus abdominis musculocutaneous free flap can restore the patient’s appearance and function. However, the rectus abdominis musculocutaneous free flap is also an invasive procedure, and it can sometimes be challenging to inset the flap such that there is enough room in the mouth for a prosthesis. In a patient who has had a maxillectomy, there is generally inadequate remaining bone stock to place osseointegrated implants for prosthetic retention. The patient’s existing dentition should be adequate to support a prosthesis. The fibula osteocutaneous free flap and other osteocutaneous flaps can be used to close the palatal defect to prevent nasal regurgitation. The fibula osteocutaneous free flap can also accept osseointegrated implants for dental restoration due to the good quality of bone stock associated with this flap. However, fibula free flap and osseointegrated implant reconstruction is a very long and extensive procedure and can require more than one surgery to fully restore this patient, particularly if osseointegrated implants are not placed during the same procedure as the free flap reconstruction.

Answer 45

The correct response is Option A. The deep circumflex iliac artery is the major blood supply to the iliac crest free flap. It gives rise to periosteal branches and nutrient endosteal branches that supply the iliac crest bone posterior to the anterior superior iliac spine. It also gives rise to an ascending branch that supplies the internal oblique muscle and several musculocutaneous perforators that supply the overlying skin, allowing a myo-osseous or osteocutaneous free flap to be harvested, respectively. Use of the iliac crest osteocutaneous free flap has been described by several authors for maxillary as well as mandibular reconstruction, and the bone itself provides ample stock for accommodating osseointegrated implants for dental restoration. The peroneal artery is the blood supply to the fibula free flap. Use of this flap is contraindicated when the peroneal artery contributes markedly to the blood supply of the distal lower extremity. The descending genicular artery is a branch of the superficial femoral artery and is the blood supply to the medial femoral condyle osseous free flap. Alternately, the medial superior genicular artery, another branch of the superficial femoral artery, can be used to supply this flap, but the pedicle is shorter. The descending branch of the lateral circumflex femoral artery is the blood supply to the anterolateral thigh free flap, which is a cutaneous perforator flap. The deep inferior epigastric artery is the blood supply to the rectus abdominis musculocutaneous free flap or the deep inferior epigastric perforator flap.

Answer 46

The correct response is Option C. Nasopharyngeal cancers are most often associated with Epstein-Barr virus (EBV) infections and arise from the mucous epithelium of the nasopharynx and are relatively rare in the United States. However, these tumors are endemic in Africa and East Asia, accounting for as many as 18% of head and neck cancers in China. Nasopharyngeal tumors are classified as either squamous cell cancers, keratinizing undifferentiated carcinoma, or non-keratinizing undifferentiated carcinoma. EBV infection is most strongly associated with the non-keratinizing undifferentiated subtype and is thought to increase malignant transformation. Nasopharyngeal cancers are most commonly treated with chemotherapy and radiation, with surgery reserved for recurrent or unusual cancers. Reconstruction of skull base defects is most commonly performed using microsurgical transfer of soft-tissue flaps. Alcohol and tobacco are the most common risk factors for head and neck cancers in general, and laryngeal cancers in particular, with cigarette smoking increasing the lifetime risk 5- to 25-fold. Other risk factors for head and neck cancers in general include cigar smoking, environmental exposures, dietary factors (red meat, betel nuts), and human papillomavirus (HPV) infection. HPV infections are most commonly associated with oropharyngeal cancers (tongue, tonsil). Significant risk factors for maxillary sinus cancers include cigarette smoking and environmental factors such as exposure to wood dust.

Answer 47

The correct response is Option A. Ameloblastomas are benign, locally invasive, odontogenic tumors accounting for 1% of tumors of the jaw and 10% of odontogenic tumors. Approximately 80% occur in the mandible and 20% occur in the maxilla. The peak incidence is in the third and fourth decades but may also arise in children and adolescents. Ameloblastomas may be radiographically found to be unilocular or, more commonly, multilocular with a “soap bubble” or “honeycomb” appearance. Treatment may be with enucleation and curettage or more radical resection. In rare cases, metastatic ameloblastoma and ameloblastic carcinomas have been reported. Fibrous dysplasia is a benign hamartomatous lesion that has a diffuse, “ground-glass” appearance on x-ray studies. It is usually treated conservatively with shaving and re-contouring of the bone. Squamous cell carcinoma is usually associated with a painful mucosal lesion. Radiographically, bony invasion may be noted in locally advanced cases. Osteosarcomas are aggressive malignancies of mesenchymal origin that exhibit osteoblastic differentiation. They are the most common primary bony cancer. Their radiographic appearance is variable and may include nonspecific destruction of the bone similar to a carcinoma, mottled ossification, similar to fibrous dysplasia, but without well-defined borders, or lamellar ossification (sheets of neo-osteogenesis). Nasopharyngeal angiofibromas are benign but locally invasive vascular tumors that occur almost exclusively in male adolescents. Their symptoms include nasal obstruction but can eventually cause facial asymmetry and eye displacement, as they grow from the region of the sphenopalatine foramen first into the nasopharynx and choanae then into the paranasal sinuses, pterygopalatine and infratemporal fossae, orbit, and even the intracranial cavity. Radiographically, they are nonencapsulated, lobular soft-tissue masses that demonstrate intense uptake of intravenous contrast due to their highly vascular nature. Extensive bony destruction is usually not a feature, but bone may be remodeled or resorbed.

Answer 48

The correct response is Option E. Nasopharyngeal angiofibromas, also known as juvenile nasopharyngeal angiofibromas, are benign but locally invasive vascular tumors that occur almost exclusively in adolescent males. Onset is most common in the second decade of life, and rarely occurs after age 25 years. Symptoms include unilateral or bilateral nasal obstruction, frequent epistaxis or blood-tinged nasal discharge, and conductive hearing loss from Eustachian-tube obstruction. In advanced stages, the angiofibroma can deform the nose, face, and orbits, as well as erode into the cranial cavity and put pressure on the optic chiasm, resulting in diplopia. Treatment is usually surgical with radiation and reserved for extensive cases such as those with intracranial extension. Preoperative embolization as well as hormone therapy with estrogens, may limit blood loss. Nasopharyngeal angiofibromas are highly vascular, and office biopsies should be avoided. Inverted papilloma is a benign, locally aggressive neoplasm that arises in the nasal cavity and is associated with squamous cell carcinoma in approximately 5% of patients. The age of onset is usually between 40 and 60 years. Surgery is the primary treatment of inverted papilloma. Encephaloceles are neural tube defects that result in sac-like protrusions of the meninges (meningocele) or brain and meninges (meningoencephalocele) in various locations along the cranium, including intranasally. They tend to be bluish, soft, compressible masses that transilluminate. Biopsy may result in a cerebrospinal fluid leak. Hemangiomas are benign vascular lesions that are present at birth and characterized by a rapid growth phase around the age of 1 to 6 months followed by gradual involution over 1 to 12 years. A hemangioma would not be expected to first occur in adolescence. Dermoid cysts are derived from ectodermal and mesodermal tissue and may contain skin, hair follicles, sebaceous glands, and sweat glands. Dermoids are usually firm and noncompressible and most frequently occur as a slow-growing cystic mass over the dorsum of the nose, but may also be entirely intranasal. Dermoid cysts may also have a dural component and should not be biopsied until intracranial communication can be ruled out by x-ray studies. Encephaloceles, hemangiomas, and dermoid cysts are congenital nasal masses that occur in infancy rather than adolescence.

Answer 49

The correct response is Option D. The best option for reconstruction in this patient requiring circumferential pharyngeal reconstruction is the anterolateral thigh flap. This fasciocutaneous flap is supplied by perforators from the descending branch of the lateral femoral circumflex vessels, which are a branch of the profunda femoris vessels. The descending branch runs between the vastus lateralis and rectus femoris muscles, not the vastus medialis and rectus femoris. The radial forearm flap is based on the septum between the flexor carpi radialis and brachioradialis muscles in the arm. Although it can be used to reconstruct partial, noncircumferential pharyngectomy defects, it is not ideal for a long, circumferential defect in a previously radiated neck. The pedicle runs between the flexor carpi radialis and brachioradialis, not the palmaris longus. The circumflex scapular artery emerges from the triangular space in the back, which is defined by the teres minor, teres major, and the long head of the triceps. It is the pedicle to the parascapular and scapular flaps. Option C defines the quadrangular space that transmits the axillary nerve and posterior humeral circumflex artery.

Answer 50

The correct response is Option D. The patient described likely has a stage III tumor (T3 N0 M0). Standard management algorithms developed by the National Comprehensive Cancer Network recommend adjuvant radiation treatment when the persistence of positive margins relates to microscopic disease and not gross disease. If there is gross disease, either by physical examination or follow-up imaging, and it is resectable, then surgical resection of the residual disease should be done initially, followed by adjuvant radiation. Chemotherapy for major salivary gland tumors is appropriate as a first-line therapy concomitant with radiation only in cases of squamous cell carcinoma. In patients with mucoepidermoid, adenoid cystic, and adenocarcinomas, the role of chemotherapy is mainly palliative and reserved for advanced situations of recurrent or distant systemic disease. The absence of standard chemotherapy protocols for these situations attests to the degree of response that can be expected. Immunotherapy has no significant role in the treatment of major salivary gland malignancies. Neck dissection is indicated for malignant salivary gland tumors with clinically positive nodes detected either on physical examination or with preoperative imaging workup. This applies to parotid tumors of either the superficial or the deep lobe. Typical imaging to identify nodal disease would include CT scan or MRI or both. Neck dissections performed electively are rarely indicated, and only in very high-risk situations that are based on factors other than clinical and histologic features of the primary tumor. Radiation treatment is an effective treatment for negative necks with high risk of nodal disease, and is preferred over elective neck dissections. Surgical resection of persistent disease is indicated when a previously treated parotid mass was incompletely resected, and the remaining tumor is gross and resectable, rather than just microscopic. If not resectable, then the patient should have definitive radiation treatment.

Answer 51

The correct response is Option A. Salivary gland tumors are relatively rare and make up about 3 to 4% of all head and neck neoplasms. The majority of salivary gland tumors (approximately 80%) originate in the parotid gland. Approximately 80% of parotid gland tumors are benign. Malignant tumors are associated with facial paralysis and pain, although they may also be asymptomatic. Malignant tumors may also metastasize to the regional lymph nodes and to distant sites. Pleomorphic adenoma, also known as benign mixed tumor, is the most common benign tumor of the parotid gland. This tumor is histologically characterized by epithelial and connective tissue elements, with stellate and spindle cells interspersed with a mixoid background. Warthin tumor (papillary cystadenoma lymphomatosum) is the next most common tumor of the parotid gland and is also benign. Warthin tumors predominantly occur in males and are bilateral in 10% of patients. Histologically, they are characterized by papillary cysts and mucoid fluid as well as nodules of lymphoid tissue. Mucoepidermoid carcinoma is the most common malignancy of the parotid gland and the second most common malignancy of the submandibular and minor salivary glands. Mucoepidermoid carcinomas contain two major elements: mucus-producing cells, and epithelial cells of the epidermoid variety. Low-grade tumors are associated with a predominance of mucus-secreting cells lining cysts and intervening nests of well-differentiated epidermoid cells. High-grade tumors show few or no mucus-producing cells and the epidermoid cells are poorly differentiated. Intermediate-grade tumors are defined by less cyst formation than low-grade tumors with nests of epidermoid and less differentiated intermediate cells. The biologic behavior of mucoepidermoid carcinomas correlates with their histologic grade. Adenoid cystic carcinoma is the second most common tumor of the salivary glands and the most common malignant tumor of the submandibular, sublingual, and minor salivary glands. It is slightly more common in female patients and typically affects patients between the ages of 30 and 70 years with a peak incidence of 40 to 59 years. There are three histologic subtypes: cribriform, tubular, and solid. The cribriform pattern has a classic “Swiss cheese” appearance with cells arranged in nests separated by round or oval spaces. The tubular pattern has a glandular architecture, while the solid (or basaloid) pattern has sheets of cells with little or no luminal spaces. Adenoid cystic carcinoma usually exhibits a protracted course characterized by indolent growth and a propensity for perineural invasion, reported to occur in 20 to 80% of patients. Distant metastases, most frequently to the lung, are not uncommon. Lymphangiosarcoma is a rare vascular tumor, which may be associated with prolonged lymphedema. These tumors are more commonly found in the extremities and under light microscopy appear as vascular channels with anaplastic endothelial cells.

Answer 52

The correct response is Option A. The most appropriate answer is dentigerous cyst. This type of cyst develops in the context of an unerupted tooth, which can be seen below the cyst. The cyst is lined with benign nonkeratinizing epithelium and is caused by degeneration of the enamel reticulum of the unerupted tooth. It is the second most common type of jaw cyst. Two thirds occur in the mandible. Gingival cysts appear most commonly on alveolar ridges of infants but can also rarely appear in adults. Their origin relates to rests of dental lamina, and, unlike dentigerous cysts, these contain keratin. Clinically, they are soft and fluctuant, and range in size between 1 and 15 mm. Primordial cysts and odontogenic keratocysts are equivalent. They develop from rests of dental lamina and basal cell hamartomas. Therefore, unlike dentigerous cysts, these are lined with a keratinizing stratified squamous epithelium that is sometimes dysplastic. Their size range is 1 to 9 cm, and pain is a common symptom. Gorlin syndrome includes the association of multiple odontogenic keratocysts with multiple basal cell carcinomas, nasal deformity, skeletal abnormalities, calcification of the falx cerebri, and palmar or plantar pits. Calcifying odontogenic (Gorlin) cysts are distinct from those above because they may be part cystic and part neoplastic. The histology shows features similar to the calcifying epithelioma of Malherbe (epithelium undergoing keratinization and calcification), and ameloblastic proliferations. Radiographically, they contain various amounts of radiopaque (calcified) material and are usually located anterior to the first molars ranging in size from 1 to 8 cm. Radicular cysts are the most common type of jaw cysts and develop at the apex of a nonviable erupted tooth, from epithelial rests of Malassez in the periodontal ligament. As these cysts are inflammatory in nature rather than developmental, they are usually preceded by a periapical granuloma. Histology shows a fibrous shell lined with nonkeratinizing stratified squamous epithelium infiltrated with chronic inflammatory cells. Due to their painless quality, they most commonly occur as an incidental finding of routine x-ray studies of the maxilla. These cysts are radiolucent, and differ from dentigerous cysts because they are located at the apex of an erupted tooth rather than at the crown of an unerupted tooth.

Answer 53

The correct response is Option C. Resection is the most appropriate management for the symptomatic lesion described in the photographs. Oropharyngeal tumors must always be biopsied to assess malignancy potential. If the tumor is then deemed to be benign, appropriate management is determined based on symptoms. This patient presented with a biopsy result and a sizable lesion that is still growing. Typically, an imaging study such as MRI is performed of the head and neck to assess the extent of the disease. For this type of isolated lesion that is ulcerating and interfering with eating, resection is the most appropriate treatment. Observation is not the best option, as the patient is symptomatic. Embolization is not indicated, as this is not a vascular structure. Sclerotherapy yields poor results with a microcystic lesion and would likely result in painful necrosis of the involved tissue. Radiation therapy is not a described treatment for benign lymphatic lesions. Carbon dioxide laser treatment has been described for these types of lesions, but it often requires multiple treatments and leaves a raw surface for healing following each treatment.

Answer 54

The correct response is Option D. Vascularized composite allotransplantation refers to the transplantation of an allograft consisting of heterogeneous cadaveric tissues. It provides a means of restoring structural, functional, and aesthetic form in severely injured patients. The potential for improvements in quality of life must be offset by the need for lifelong immunosuppression in adults with non-life-threatening injuries. The benefits and difficulties of immunosuppressive drugs have been established in solid organ transplantation. Regimens derived from renal transplantation have been successfully applied to composite tissue allografts. Overall, more than 60 hand/forearm/arm transplantations and 16 face transplantations have been performed in the past 12 years. The overall functional and aesthetic outcome is satisfactory, but side effects and complications related to immunosuppression are challenges hindering progress in this field. The high levels of immunosuppression, skin rejection, nerve regeneration, donor legislation, and the acceptance level need to be addressed to promote growth of this promising new field in transplantation and reconstructive surgery. Because composite tissue allograft transplantations are not life-saving procedures, much consideration is devoted to the issue of minimizing or withdrawing immunosuppression. When compared with solid organ transplants, composite tissue allografts are histologically heterogeneous, composed of different tissue types (e.g., skin, muscle, bone, bone marrow, lymph nodes, nerve, and tendon) and express different immunogenicity of transplanted elements. The hierarchy of antigenicity of composite tissue allografts was introduced in an experimental model of limb transplantation and showed that skin is the most antigenic tissue, and together with muscle, subcutaneous tissue, and bone (including bone marrow), may generate high immunologic response. The vascularized muscle component of limb allografts may induce a cell-mediated response greater than the skin; however, muscle as a single component is less antigenic than skin. Bone represents lower immunogenicity, and cartilage, tendon, and vessels are the least antigenic.

Answer 55

The correct response is Option C. The patient described has severe radionecrosis of the skin and the underlying bone from the previous radiation therapy. The skin is thinned, and spontaneous necrosis with scabbing can be seen in the photograph and will require extensive debridement including necrotic skin and underlying bone. As a result, closure with scalp rotation flaps will be inadequate because of the extensive skin damage, size of the defect, and exposed underlying dura. Similarly, bone burring will not be possible even if the underlying calvaria was preserved due to the history of radiation. Negative pressure wound therapy is not an option due to exposure of the underlying dura and brain matter. Similarly, acellular dermis will not be effective due to the damaged underlying tissues and chronic contamination. Radical debridement and coverage with a free flap (e.g., latissimus flap) will offer the best option for reconstruction in this patient because this procedure will deliver healthy vascularized tissues to cover the exposed cranial structures.

Answer 56

The correct response is Option D. This is an extensive subtotal maxillectomy (Type IIIA Cordeiro classification) that requires reconstruction of a number of anatomical structures including the hard palate, the orbital floor, and the nasal lining. In addition, vascularized tissues are required to separate the maxillary sinus content from the orbit. In this case, the rectus flap is the best option because it can provide skin to re-line the maxillary sinus and repair the palatal defect. In addition, the rectus flap has sufficient bulk to obliterate the maxillary sinus and provide vascularized tissue to support the orbital floor reconstruction that is required. The omentum flap usually has enough bulk to obliterate the sinus but will not enable reconstruction of the palatal defect. The obturator will reconstruct the palate but will not provide vascularized tissue to line the orbital floor reconstruction and separate this region from the maxillary sinus. The temporalis flap can be used to cover the orbital floor reconstruction but does not reconstruct the palatal defect. The facial artery musculomucosal flap is a flap based on the facial artery and would not be useful in this reconstruction.

Answer 57

The correct response is Option C. The salivary gland neoplasms are uncommon and generally benign. Most benign tumors can be easily cured by wide local excision. Pleomorphic adenoma is the most common salivary gland tumor, with a propensity for local recurrence. Simple enucleation is discouraged. Removal is usually done by a superficial parotidectomy. The superficial lobe is anatomically defined by the traversing facial nerve. The nerve is preserved, as pleomorphic adenoma is a benign tumor that does not infiltrate the nerve. The parotid gland is also the most frequently affected major salivary gland, and the palatal salivary tissue is the most commonly affected minor salivary gland. Pleomorphic adenomas are the most common neoplasm of salivary glands, comprising 45 to 75% of all tumors in most series. These tumors typically affect patients in their 20s to 50s and there is a female predilection. Warthin’s tumor is the second most common tumor of the salivary glands and constitutes approximately 14 to 21% of salivary gland neoplasms. The tumor is almost exclusively found in the parotid gland, typically affects males in their 50s to 60s, and often may be bilateral.

Answer 58

The correct response is Option C. The radial forearm fasciocutaneous free flap is the most appropriate reconstructive choice among those listed. It is generally a thin, pliable flap with a long pedicle and vessels of adequate caliber for straightforward microvascular anastomosis. The physical characteristics of this flap are well-suited to preserving the mobility of the remaining hemitongue, resulting in reasonable speech and swallowing function following surgery in most cases. The primary goals of reconstruction following hemiglossectomy include watertight wound closure such that oral secretions do not communicate with the neck contents and result in a fistula, and restoration of speech and swallowing function by preserving the mobility of the remaining native tongue. Primary closure would result in severe tongue tethering and impaired speech and swallowing. Although likely to contract less than a split-thickness skin graft, a full-thickness skin graft may also restrict mobility of the tongue and is unlikely to achieve a watertight wound closure. The submental artery island flap is based on a branch of the facial artery that can be used to close defects up to approximately 7 × 18 cm, depending on neck skin laxity. This flap is generally unreliable following neck dissection in which the facial artery and its branches may be ligated. The rectus abdominis musculocutaneous free flap is a highly reliable free flap but is often too bulky to permit optimal mobility of the remaining tongue, especially in patients with truncal obesity.

Answer 59

The correct response is Option B. The patient describes velopharyngeal insufficiency post-soft palate resection. Prosthetic obturation is the traditional means of reconstructing palatal defects. After 12 months, observation has already been performed without resolution of symptoms. Skin grafting of soft palatal defects is of little use because it does not adequately reestablish the bulk necessary for through-and-through palatal defects, therefore leading to contracture and palatal dysfunction. Tracheotomy would exacerbate speech and swallowing difficulties and therefore is not appropriate. Injecting the inferior turbinates with corticosteroids would not functionally correct the velopharyngeal insufficiency and is therefore not appropriate.

Answer 60

The correct response is Option A. When dealing with a near or total circumferential defect of the laryngopharyngeal unit, function must be considered as well as incidence of strictures and fistulas. Many of these patients receive a tracheoesophageal puncture prosthesis (TEP) for speech and many are quite intelligible after rigorous therapy. Speech with fasciocutaneous flaps, such as the anterolateral thigh flap and the radial forearm, is consistently better than with jejunal free flaps. In one study, a direct comparison between these flaps was performed, and 78% of patients used tracheoesophageal speech for conversation when reconstructed with an anterolateral thigh free flap compared with only 25% following a jejunal free flap. The distensibility and mucous production in reconstructions using a jejunal free flap appears to be responsible for the low-pitched, “wet” speech. There is some evidence that intensive speech rehabilitative programs can produce excellent results with jejunal flaps. A pedicled muscle flap is typically used to cover laryngeal or laryngopharyngeal closures, especially in radiation salvage cases. A silastic stent is usually used as salivary diversion while the reconstruction is healing. During its occupancy, no TEP speech can be generated. A gastric pull-up is usually used when a large portion of the cervical esophagus is involved with tumor, and thus a laryngopharyngoesophagectomy is performed so that the anastomosis of the swallowing system is cephalad to the thorax.

Answer 61

The correct response is Option C. The Karapandzic technique involves performing circumoral incisions, mobilizing the orbicularis oris muscle, and preserving the nerves as well as the vascular supply to the lips from the superior and inferior labial arteries. The advantage of Karapandzic flaps is that they maintain a continuous circle of functioning orbicularis muscle, which helps to restore oral competence. Microstomia can occur, but is usually less of a problem in older patients who have greater tissue laxity. The optimal method for lip reconstruction depends on the size of the defect, the location of the defect, and the laxity of the remaining tissues. Primary closure can lead to excellent cosmetic and functional results but is restricted to wounds less than one third to one half of the lip width. The Estlander flap is a full-thickness lip transposition flap that borrows tissue from the opposite lip and can be used to reconstruct defects up to two thirds of the lip width. However, the Estlander flap is specifically designed to restore defects of the oral commissure. The Abbé flap is also a transposition flap that “steals” tissue from the opposite lip and is used for central defects, but must remain pedicled by a bridge of lip for several weeks, severely restricting mouth opening during that time. The radial forearm fasciocutaneous free flap is used for total lower lip defects, particularly in situations where sufficient cheek tissue cannot be recruited to close the defect (which is known as the Webster-Bernard technique). Suspension of the folded radial forearm flap over a palmaris longus tendon graft secured to the maxillary bone helps prevent flap ptosis that can result in loss of oral competence, a major problem that can occur with this technique. The facial artery musculomucosal (FAMM) flap is a pedicled flap consisting of buccal mucosa and a portion of the buccinator muscle that can be useful for reconstructing the vermillion lip, but not the cutaneous portion of the lip. Also, because the FAMM flap is based on the facial artery, it may not be reliable following a neck dissection in which the facial artery has been ligated.

Answer 62

The correct response is Option A. The patient described has a sialocele, either from a leak at the site of the parotid duct repair or from direct injury to the gland. An abscess is less likely, given the prophylactic antibiotic treatment, no erythema, and no fever. Most occurrences of sialocele after parotid duct injury or repair will resolve with compression with or without repeated aspiration. Anticholinergic medications may help by decreasing salivary flow. External drainage of a sialocele may result in a fistula and should be avoided. Spontaneous external fistulas after parotid duct repair may be treated with intraoral drainage and compression. If the sialocele persists, excision of the cyst or pseudocyst may be required, with intraoral drainage over a stent, but this would not be appropriate initial management. Attempts to revise the parotid duct repair would not likely be fruitful because of postoperative inflammation and unnecessary if an adequate stent were in place and compression were applied. Ligation is indicated for initial management of proximal injuries to the parotid duct. Significant swelling of the parotid gland will generally occur after this procedure but typically resolves rapidly with atrophy of the gland.

Answer 63

The correct response is Option B. The circumflex scapular artery is the blood supply to the scapular bone or osteocutaneous free flap. The pedicle can be extended by including the subscapular artery and vein proximally. This flap can be designed as a chimeric flap to include the latissimus dorsi and serratus anterior muscles based on the thoracodorsal artery, another branch of the subscapular system, to reconstruct complex defects that involve multiple tissue types. The scapular flap can also be based on the angular branch of the thoracodorsal artery. One disadvantage of the scapular flap is that it is on the back, usually precluding simultaneous oncologic resection and flap harvest to save operative time. Composite bony reconstruction is indicated for the expected mandibular defect. Soft-tissue reconstruction alone for anterior mandibular defects is associated with significant cosmetic deformity as well as impaired masticatory, speech, and even swallowing function. The fibula osteocutaneous free flap, based on the peroneal artery, not the anterior tibial artery, is favored by many surgeons based on its generous bone length and good quality bone stock. However, the flap is contraindicated when blood supply to the distal lower extremity is compromised, such as in advanced peripheral vascular disease (also known as peripheral arterial disease, or PAD). The thoracoacromial artery is the blood supply for the pectoralis major muscle or myocutaneous pedicled flap, which is a soft-tissue flap that would not satisfactorily restore this patient’s appearance and function. An osteomyocutaneous variant of the pectoralis major flap that incorporates the fifth rib has been described, but would not be a first-line option due to limited reach of the flap and the tendency to tether the reconstructed jaw to the neck as scar contracture occurs. The superficial circumflex iliac artery is the blood supply to the groin free flap, which is a soft-tissue flap without a bony component and, therefore, not appropriate for reconstructing the anticipated defect. The supraclavicular artery is the blood supply to the supraclavicular artery island pedicled flap, which is a soft-tissue flap that would be also inadequate to reconstruct this large bony defect.

Answer 64

The correct response is Option D. This patient has an ameloblastoma, which is a rare cystic tumor involving the mandible. Characteristic findings include a multilocular radiolucent lesion with a ?soap bubble? appearance, usually in association with an impacted molar. X-ray studies show unilocular or multilocular cystic masses associated with thinning of the surrounding bone. Examination of a biopsy specimen shows palisading odontogenic cells. Appropriate treatment consists of segmental mandibular resection, including a margin of normal bone and any adjacent teeth, and immediate reconstruction. Immediate reconstruction will rapidly restore facial function and improve facial aesthetics. Curettage is inadequate and is associated with a recurrence rate of 50 to 100%. Ameloblastomas are generally benign. Malignant forms of ameloblastoma may occasionally be treated with adjuvant radiation therapy in addition to surgical resection.

Answer 65

The correct response is Option C. Reconstruction of mid face defects after oncologic resection is challenging. The defect described involves a large portion of the mid face with resection of the hard palate and orbital floor (Cordeiro type IIIb). Therefore, reconstruction should aim to provide closure of the palate, support for the orbit, and contour for the cheek. Of the choices given, the free rectus abdominis flap with iliac crest bone graft is the most appropriate option because it provides volume for reconstruction of the maxillary defect, closure of the palatal defect, and support of the eye structures with an iliac crest bone graft. The dorsalis pedis flap is not an appropriate choice because of its low volume and donor site defect. The free radial forearm flap lacks sufficient volume to reconstruct this extensive defect of the mid face. The pedicled pectoralis flap does not reach this mid face defect reliably. The pedicled temporalis flap with vascularized split calvarial bone flap similarly does not reach this defect because of its short arc of rotation.

Answer 66

The correct response is Option D. The parotid and submandibular glands are the main contributors to salivary flow. Minor salivary glands are present in the oral cavity and pharynx. They are minor contributors, creating less than 10% of the saliva. The secretory unit of the salivary glands is constructed of acinar cells, myoepithelial cells, intercalated duct, striated duct, and excretory duct. The acini are responsible for secreting serous and mucous constituents of saliva. The parotid gland is purely a serous-secreting gland, whereas the submandibular is predominately serous, with 10% of the acinar cells producing mucous secretions. In the unstimulated state, the submandibular gland produces most of the saliva, whereas the parotid gland is responsible for most of the saliva produced in the stimulated state. Total salivary flow can reach 1.5 L daily in healthy individuals. Xerostomia is a common complication resulting from radiation therapy for head and neck cancer. Xerostomia is defined as dry mouth (reduced or absent saliva flow) caused by damage to the salivary glands. Xerostomia has late effects on oral health, specifically dry mouth, sore throat, altered taste, dental decay, changes in voice quality, and impaired chewing and swallowing function. Xerostomia may also contribute to the development of mandibular osteoradionecrosis after radiation. Salivary flow reduces to 50 to 70% of baseline after 10 to 16 Gy radiation and is undetectable after 40 to 42 Gy radiation. Xerostomia has been reported to occur in 60 to 90% of survivors of head and neck cancers treated with radiation therapy. Management of xerostomia is focused on prevention and treatment. Although there are multiple options and advances that have been made in the management of this condition, there are no specific regimens that will prevent or completely treat xerostomia. Prevention of xerostomia includes cytoprotection using amifostine or pilocarpine. Radiation therapy techniques that spare the salivary gland may be more effective than cytoprotective agents. Such techniques include the use of intensity-modulated radiation therapy to spare the parotid gland and submandibular gland. Surgical submandibular gland transfer has also been described. Treatment of radiation-induced xerostomia includes salivary substitutes, salivary stimulants, acupuncture, and gene therapy.

Answer 67

The correct response is Option C. Failure to reconstruct the anterior mandibular bone results in the so-called ?Andy Gump? defect and is associated with disfigurement, as well as impaired speech, swallowing, and mastication. Of the choices listed, the fibula osteocutaneous free flap is the most reliable reconstruction of the anterior mandible, particularly when radiation therapy is administered. The fibula provides a large amount of good-quality bone stock than can tolerate osteotomies, which are needed to restore the shape of the anterior mandible. A skin paddle based on perforating vessels from the peroneal artery can be included to simultaneously reconstruct the floor-of-mouth mucosal defect. Age alone is not a contraindication to reconstruction with a microvascular free flap, provided the patient is in otherwise good medical condition and has patent blood circulation to his distal lower extremity. A nonvascularized iliac crest bone graft can be used to reconstruct small mandibular defects (under 5 cm in length), but will most likely not tolerate radiation, so it would not be a good option in this case. Mandibular reconstruction with a titanium plate, alone or covered with a soft-tissue flap, such as the pectoralis major myocutaneous pedicled flap, is associated with a very high rate of complications, including infection, exposure, and plate fracture, particularly in the setting of an anterior location and radiation therapy. The radial forearm fasciocutaneous free flap can be used to close the floor-of-mouth mucosal defect, but will not restore the bony mandible. The supraclavicular island pedicled flap is based on the supraclavicular artery, a branch of the transverse cervical artery, and can be used to close oral soft-tissue defects, but, like the radial forearm fasciocutaneous free flap, will not restore the mandible.

Answer 68

The correct response is Option E. Osseointegrated prostheses are currently used to anchor dental crowns, auricular and facial prosthetics, and hearing aids (bone-anchored hearing aids, or BAHAs). This technology has improved since it was first introduced, and long-term survival rates are generally good. Several studies have confirmed short to intermediate survival rates of around 95% for dental prostheses in nonirradiated free fibula flap reconstruction. The results are significantly worse in irradiated tissues.

Answer 69

The correct response is Option D. These orbitofacial tumors may be part of a syndrome of neurofibromatosis 1 (NF1), which is an autosomal dominant disorder. When the full syndrome is present, skeletal dysplasia such as absence of the greater wing of the sphenoid (5 to 7%) and macrocephaly may be present. However, solitary neurofibromas unassociated with other features are not uncommon. There are three subtypes of neurofibromas: localized, plexiform, and diffuse. About 30% of plexiform neurofibromas outside of the central nervous system are associated with NF1, and the remainder are isolated. The tumors of NF2 are nearly all confined to the central nervous system and are similar to schwannomas. The scenario describes a case of plexiform neurofibroma. The majority of plexiform neurofibromas are present at birth, and half are found in the head and neck region. These tumors tend to grow in the prepubescent ages as a result of hormonal stimuli. Pathology is distinctive, and there is a 13% rate of malignant transformation. Surgical debulking and reconstruction remains the best treatment option. Cobb syndrome consists of a capillary malformation in the midline scalp region overlying an encephalocele, or in the skin posterior to an area of dysraphism in the cervical or lumbosacral spine. It does not involve the face or orbit. Fibrous dysplasia is an overgrowth syndrome of bones only, due to abnormal proliferation of bone-forming mesenchyme. It does not involve soft-tissue hypertrophy, nor is it associated with vascular malformations. Albright syndrome is a specific variety of polyostotic fibrous dysplasia and includes endocrine abnormalities and café-au-lait spots. Klippel-Trénaunay syndrome is a capillary-lymphatic-venous malformation typically involving hypertrophy of the extremities and sometimes the thorax of one side of the body, and does not involve the head and neck. The skin surface shows deep red staining with hemolymphatic vesicles. A pathognomonic feature of this condition is the presence of the embryonal lateral vein of Servelle in the lower extremity. Parkes-Weber syndrome is similar to Klippel-Trénaunay syndrome in that it may be confined to an upper or lower extremity. Overgrowth of the extremity is characteristic along with microscopic arteriovenous fistulas, and unlike Klippel-Trénaunay, lymphatic anomalies are rare. It does not involve the head or neck. Sturge-Weber syndrome is characterized by capillary malformations in the distribution of the ophthalmic or the maxillary division of the trigeminal nerve, and may be unilateral or bilateral. Frequently, there is also gradual enlargement and hypertrophy of the cheek, lip, maxilla, and occasionally the mandible. MRI may show additional vascular anomalies of the leptomeninges and choroid plexus.

Answer 70

The correct response is Option B. Merkel cell tumors are rare neuroendocrine tumors that are highly aggressive. Even despite wide surgical resections, up to one third of patients with Merkel cell tumors have local recurrences. The 5-year mortality rate of Merkel cell tumors is approximately 33%. This is more than double the mortality rate of malignant melanoma (15%). Merkel cell tumors are best treated with wide local excision and sentinel lymph node biopsy. Adjuvant radiation therapy is also used; however, radiation alone is not considered to be the best treatment. Finally, Merkel cell tumors usually arise in sun-damaged skin of the head and neck, not intraoral structures.

Answer 71

The correct response is Option D. The scenario described, Nevoid Basal Cell Carcinoma Syndrome (Gorlin syndrome, NBCCS), is rare but noteworthy. NBCCS is an autosomal dominant syndrome. Diagnosis of NBCCS is made in the presence of either two major criteria or one major and two minor criteria. The major criteria consist of the following: (1) more than two basal cell carcinomas or one basal cell carcinoma in patients younger than age 20 years; (2) odontogenic keratocysts of the jaw (proven by histologic analysis); (3) three or more palmar or plantar pits; (4) bilamellar calcification of the falx cerebri; (5) bifid, fused, or markedly splayed ribs; and (6) a first-degree relative with NBCCS. Odontogenic keratocysts are seen in 74 to 80% of patients. They usually begin to develop in the first decade (after age 7 years), with the peak incidence in the second and third decades. They are more common in the mandible than in the maxilla. They are usually asymptomatic, but they may cause pathologic fracture, swelling, loose teeth, or displacement of developing permanent teeth. Ameloblastoma has been reported with NBCCS but is very rare. Although other tumors such as fibrosarcoma, rhabdomyosarcoma, and meningioma have been reported to have increased incidence, osteosarcoma and cancers that spread to the mandible have not been reported with increased frequency in patients with NBCCS. Finally, recognition of syndromic causes of skin cancer allows for proper questions regarding family medical history, as well as the appropriate workup for potentially more threatening occult pathologies. Diagnosis of such a syndrome also sets the stage for appropriate genetic counseling.

Answer 72

The correct response is Option A. Ameloblastomas are benign, locally invasive odontogenic tumors accounting for 1% of tumors of the jaw and 10% of odontogenic tumors. Approximately 80% occur in the mandible and 20% occur in the maxilla. The peak incidence occurs in the third and fourth decades of life but may also arise in children and adolescents. On x-ray study, ameloblastomas may be unilocular or, more commonly, multilocular with a ?soap bubble? or ?honeycomb? appearance. Treatment may include enucleation and curettage or more radical resection. Segmental mandibulectomy with immediate reconstruction is favored currently and is associated with the lowest recurrence rates. In rare cases, metastatic ameloblastoma and ameloblastic carcinomas have been reported. Dental abscesses are infectious processes and present with pain, acute swelling, and fever. CT scans are usually not necessary, although periapical x-ray studies and pantomography are usually obtained. Fibrous dysplasia is a benign hamartomatous lesion that has a diffuse, ?ground-glass? appearance on x-ray study. It is usually treated conservatively, with shaving and recontouring of the bone. Osteoradionecrosis is a late complication related to radiation therapy for cancer. It is often associated with pain, bone exposure, and, as a late finding, orocutaneous fistula. Findings upon CT scan include cortical erosion and loss of bony trabeculation within the marrow space. Pathologic fractures may also be present. Squamous cell carcinoma is rare in young people who do not smoke cigarettes, but it can occur. It is usually associated with a mucosal lesion. On x-ray study, bony invasion may be noted in locally advanced cases.

Answer 73

The correct response is Option B. This question illustrates the increasing knowledge of perforators and their distribution in flap harvesting. In the case of the fibula, many septo- and musculocutaneous perforators arise from the peroneal artery and can be used to fashion independent skin islands. Because of the experience in understanding vascular territories, safe isolation of bone, skin, and muscle components of the fibula free flap can independently be performed based on their own perforators. Both the free flap and pedicled latissimus flap have been described for reconstruction of lateral mandibular defects. They allow for a large sheet of skin that can be de-epithelialized and used, albeit bulkily, for through-and-through defects. If more proximal dissection of the thoracodorsal pedicle is used to the subscapular artery, so-called ?mega flaps? of latissimus with scapular bone and/or serratus anterior musculocutaneous components are other options. The iliac crest free flap allows for large components of bone with a skin paddle. The skin, however, is neither pliable nor independent of the bone. With the addition of the internal oblique muscle to line the oral cavity and the skin used for cheek replacement, a through-and-through defect can be reconstructed with this flap. The osteocutaneous radial forearm flap provides thin and pliable skin that can be de-epithelialized for through-and-through defects. Separate skin paddles have been devised for this flap, but they are hard to center on the bone for such a defect. In addition, the bone is rather thin and cannot accommodate osteointegrated implants. The donor site has to be managed carefully as poor attention to detail (including poor patient selection) could leave the patient at risk for pathologic fracture of the radius remnant. The osteomuscular dorsal scapular flap is a variant of the pedicled osteocutaneous trapezius flap with a portion of scapular bone and provides an alternative technique for bone and skin defects. Like the latissimus pedicled flap, it provides one skin paddle and transports limited bone, and is generally reserved for patients with smaller defects and severe neck vasculopathy. Before recent understanding of perforator distribution, the scapular/parascapular free flap with bone was the flap of choice. It, unlike the fibula free flap, requires repositioning of the patient and nonsimultaneous harvesting.

Answer 74

The correct response is Option B. First-line treatment for a large, problematic infantile hemangioma is prednisolone, a corticosteroid. Almost all infantile hemangiomas will respond to oral prednisolone as long as the correct dose is given (3 mg/kg/day). Response is considered either stabilization (the tumor no longer enlarges) or accelerated regression (the lesion becomes smaller). Corticosteroids are very safe; no long-term adverse effects have been reported for children treated for infantile hemangioma. Unlike patients who receive chronic, high-dose corticosteroids for transplants or autoimmune disorders, infants with infantile hemangioma are only treated for a few months, and the dose is rapidly weaned as they gain weight and the physician lowers the dose. Interferon is no longer used for patients with infantile hemangioma because it causes spastic diplegia. Propranolol, a beta blocker, recently has been shown to have activity against infantile hemangioma. However, its efficacy and safety compared to corticosteroids have not been studied. Complications such as hypotension and hypoglycemia have been reported, and infants require close monitoring after the initiation of therapy. Pulsed-dye laser treatment for a cutaneous, proliferating infantile hemangioma is contraindicated. The laser cannot penetrate into the deep dermis or subcutaneous tissue and thus has minimal efficacy. In addition, the laser delivers a thermal injury to the already compromised skin and has been shown to increase the risk of ulceration, pain, and scarring. Resection of a large, proliferating parotid hemangioma is contraindicated. During infancy, the tumor is highly vascular and the patient is at risk for major blood loss and facial nerve injury.

Answer 75

The correct response is Option B. Salivary gland tumors frequently occur within the parotid gland, and the vast majority (75%) of parotid tumors are benign. In older children, however, parotid tumors are much more likely to be malignant (50%). In young children, the most common diagnosis is hemangioma. As in the scenario described, the lesion appears to be benign, and, in this age group, malignancy is rare. In older children, mucoepidermoid carcinoma is most common, as in adults. Adenocystic carcinoma, or cylindroma, is infrequent in the parotid gland (7%) but quite common in the minor salivary glands (35%). It is a slow-growing mass, often associated with pain and facial palsy. These tumors are aggressive, with one third to one half of affected patients developing metastatic disease. Adenocarcinomas comprise 10% of malignant parotid gland tumors. These tumors vary according to grade and histologic appearance. They occur most frequently after the fifth decade of life and commonly involve the minor salivary glands. In the parotid gland, they manifest as fixed masses characterized by occasional pain or facial palsy. Mucoepidermoid carcinoma is the most common malignancy of the parotid gland. It is rarely bilateral. It may be low-grade or high-grade. Low-grade tumors are slow-growing and indolent; high-grade tumors are much more aggressive. The recurrence rate of high-grade tumors is increased, and the facial nerve is frequently affected. Pleomorphic adenomas, or benign mixed tumors, are the most common salivary gland neoplasms, comprising about 60% of all salivary gland tumors and 80% of benign tumors. They occur as painless salivary masses that are firm and well circumscribed. Facial weakness is not found. Bilateral tumors are rare. This tumor is treated by resection, and in rare cases (recurrence), can transform into a malignant mixed tumor. Warthin tumor is a common neoplasm of the parotid gland, accounting for 10% of all parotid tumors. These tumors are usually painless and tend to grow slowly, oftentimes over a period of several years. They are more common in older men and are frequently bilateral. Warthin tumors are usually treated with superficial parotidectomy with only minimal margins needed. Recurrence is common.

Answer 76

The correct response is Option C. The planned resection in the patient described is a total laryngopharyngectomy resulting in a circumferential defect of the pharynx. The goals of reconstruction are to restore the continuity of the gastrointestinal tract while avoiding fistula formation and donor site/recipient site deformities. The most appropriate reconstructive option that meets these requirements for a circumferential defect of the pharynx is a free jejunum flap. The free jejunum flap rapidly restores pharyngeal continuity and has high success rates in large series. Although the patient described is at risk for fistulas because of previous surgery and chemoradiation, most pharyngeal leaks seal spontaneously after free jejunum transfer. Tubed fasciocutaneous flaps (eg, radial forearm or anterolateral thigh flaps) can also be used for circumferential defects of the pharynx; however, musculocutaneous flaps such as latissimus dorsi or pectoralis major flaps are secondary choices because they are associated with significant bulk. This bulkiness usually requires skin grafting of the neck and in some instances may occlude the tracheostomy. In addition, the excess bulk associated with musculocutaneous flaps makes tubing the skin paddle difficult and prone to breakdown caused by excessive tension. Finally, in order to tube a musculocutaneous flap, large skin flaps are necessary (because of the excess bulk associated with the muscle) and often require skin grafting of the donor site. Donor site skin grafting can be a significant source of morbidity and may be associated with wound-healing complications. Bilateral deltopectoral flaps can be used for treatment of circumferential defects of the pharynx; however, they are associated with high leak rates and require multiple stages. A cervical esophagostomy would not restore continuity of the pharynx and would result in a significant diminution of quality of life.

Answer 77

The correct response is Option A. Large defects of the upper medial cheek are best repaired with local skin. The wound described is too large to be repaired primarily without significant distortion of the lower eyelid. Cervicofacial flaps can be used for moderate-to-large defects of the upper medial cheek with tension-free closure. These flaps are particularly useful in older patients with loose skin. Tension-free closure is critical for avoiding lower eyelid complications. A deltopectoral flap is useful for reconstruction of defects of the neck or lower face. It is not appropriate in the patient described. Tissue expanders may be placed adjacent to the defect; however, they should not be used in a patient with an open wound. Use of tissue expanders in this manner would result in an excessive risk of extrusion. Primary closure along the relaxed skin tension lines with wide undermining would result in excessive tension on the wound, resulting in distortion of the lower eyelid. Split- or full-thickness skin grafts could be used to reconstruct the defect in the patient described; however, the aesthetic result would be suboptimal.

Answer 78

The correct response is Option C. The patient described has osteoradionecrosis of the mandible, a complication that occurs in up to 40% of patients receiving adjuvant radiation therapy for head and neck malignancies caused by hypoxia, hypovascularity, hypocellularity, and impaired collagen synthesis. The traditional definition is an area of exposed, irradiated bone that is nonhealing over 3 months. Treatment depends on the severity of the disease. Debridement and antibiotic therapy, plus or minus hyperbaric oxygen therapy, with soft-tissue reconstruction as needed, may be curative in up to 90% of cases of osteoradionecrosis limited to the alveolar ridge or mandible superior to the alveolar canal. When more extensive destruction of the mandible is present, or when there is a pathologic fracture, as seen in the scenario described, resection of all the necrotic bone and soft tissue is indicated, followed by reconstruction with vascularized bone and soft tissue. Successful healing occurs in up to 80 to 90% of patients with more extensive disease when treated in this way. Local flaps are of limited use for soft-tissue coverage because of the radiation.

Answer 79

The correct response is Option B. The patient described has osteonecrosis of the mandible and an orocutaneous fistula caused by bisphosphonate (Zometa) therapy. Bisphosphonates bind to calcium crystals in the bone and are resistant to degradation by alkaline phosphatase. As such, they inhibit osteoclast-mediated bone resorption. They are used in the treatment of osteoporosis and, in higher doses, for treatment of bone metastases. Although they are an important tool in cancer therapy, bisphosphonates can initiate osteonecrosis of the jaw, particularly in the presence of trauma, infection, foreign body, and radiation injury. Prevention with oral hygiene and avoidance of invasive dental procedures is important. However, once osteonecrosis occurs, it must be treated. Treatment often consists of stopping bisphosphonate therapy and thorough debridement of bone with removal of hardware. More extensive surgical intervention is determined on a case-by-case basis. In the scenario described, the patient was treated with a marginal mandibulectomy, removal of involved dental implant posts, and a submental artery flap to cover the floor-of-mouth defect and seal the orocutaneous fistula. Although bevacizumab (Avastin) and dexamethasone (Hexadrol) have been associated with poor wound healing, and doxorubicin (Adriamycin) and cetuximab (Erbitux) have been associated with mouth sores, none has been associated with osteonecrosis.

Answer 80

The correct response is Option C. In the scenario described, bony reconstruction will not impact function, and therefore soft-tissue coverage is adequate. A scalp flap is the most appropriate option because it will bring in blood supply and soft-tissue coverage without the risks associated with extended general anesthesia. Skin grafting would likely not heal in a radiated bed. The long history of a draining wound is a contraindication to the use of alloplastic material. Although a rib graft would provide bony support, it would also increase risk because of the donor site morbidity in the patient described, who has chronic obstructive pulmonary disease and is at high risk for postoperative pneumonia.

Answer 81

The correct response is Option D. Complications of free jejunal transfer include thrombosis and flap loss, salivary fistula, and stricture. Thrombosis and flap loss typically occur in the first few days after surgery. Because of the poor ischemic tolerance of the jejunum flap, thrombosed flaps are rarely salvageable. In these instances, early debridement and repeat free flap reconstruction is the best approach. The instance of salivary fistula is approximately 10%, with the majority of patients having received prior radiation therapy. Postoperative salivary fistula after free jejunal transfer can usually be treated conservatively with maintenance of nothing by mouth (NPO) status, dressing changes, and wound care. Larger and more persistent leaks may respond to advancement of wound edges and local flap closure with T-tube decompression of the bowel segments, or pectoralis myocutaneous flap reinforcement of the wound closure. In the setting of a viable free tissue transfer, conservative measures are the most appropriate initial management of this complication.

Answer 82

The correct response is Option C. The radial forearm flap is based on the radial artery and its vena comitans. In addition, the cephalic vein can usually be harvested together with the flap to provide venous outflow. In the patient described, the radial forearm flap is the best choice because it provides a thin, pliable skin paddle suitable for repair of a hemiglossectomy defect. In addition, the long pedicle vessels enable anastomosis to the contralateral neck. The scapula flap can be used in this defect; however, the flap is more bulky. The latissimus flap and the rectus flap are similarly too bulky for a hemiglossectomy and are better choices for a total glossectomy. Finally, the jejunum flap is not useful for a hemiglossectomy defect and is used most commonly for circumferential pharyngeal defects.

Answer 83

The correct response is Option E. The lesion described is a classic angiosarcoma. The most common form of this disease is cutaneous angiosarcoma without lymphedema in elderly patients. The highest incidence occurs in patients over 70 years of age, with a 2:1 male-to-female predilection. At least half of these tumors involve the head and neck. Lesions typically present as deceptively benign-appearing bruise-like patches on the central face, forehead, or scalp. Facial swelling and edema may be present. More advanced lesions are violaceous and contain elevated nodules that bleed easily. Ulceration may be present. The lesion gradually spreads and eventually covers large portions of the head and neck. Prognosis is invariably poor with a less-than-15% survival rate over a 5-year period. Surgical excision with wide margins and immediate reconstruction is the most appropriate initial management. In spite of aggressive initial surgical management, the goal of histologically negative margins is extremely difficult to achieve in this disease process. Given the poor results obtained with surgery alone, radiation therapy has been offered as the best possible adjuvant therapy. However, there is no proof that radiation therapy provides benefit. Adjuvant chemotherapy offers no statistically significant benefit for survival, although one agent that appears to have some activity against this disease is paclitaxel. Immunomodulators, such as interferon or interleukin, may be successful alternatives to chemotherapy, but data are lacking. There is no role for cryotherapy in the management of angiosarcoma.

Answer 84

The correct response is Option C. The patient described has an advanced (stage IV) cancer of the floor of the mouth. The most appropriate treatment for the primary cancer is segmental mandibulectomy, reconstruction with a fibula osteocutaneous free flap, and postoperative radiation therapy. A marginal mandibulectomy is defined as excision of the alveolar process, sparing a portion of the mandible. It is performed when the cancer abuts or is adherent to the mandibular periosteum but does not invade the bone. Reconstruction after marginal mandibulectomy is performed by primary closure, secondary intention, skin grafting, or free flap, depending on the size and nature of the defect. For segmental mandibular defects of the anterior mandible, reconstruction with vascularized osseous or osteocutaneous flaps, such as the fibula osteocutaneous free flap, is preferred, particularly when postoperative radiation therapy is planned. Reconstruction of the anterior mandible using a titanium reconstruction plate and soft-tissue free flap or pedicled flap is associated with a high rate of complications. Postoperative radiation therapy results in good local control in patients with floor-of-mouth cancers, but it is associated with poor survival rates in advanced-stage cancers when used as a single treatment modality.

Answer 85

The correct response is Option D. A radial forearm free flap is the most appropriate reconstructive option for the patient described. A dorsal tongue flap would be difficult to inset in the floor of the mouth and would create additional tethering. A large defect of the floor of the mouth with a marginal mandibulectomy would be difficult to close with a local flap in a patient who has undergone radiation. An osteocutaneous fibular free flap is inappropriate because there is no segmental mandibular defect with a marginal mandibulectomy. A split-thickness skin graft would be inappropriate to place on exposed bone.

Answer 86

The correct response is Option B. Tumors of the oral cavity and oropharynx are staged according to the TNM (tumor, node, metastasis) system. A tumor with dimensions greater than 2 cm but less than or equal to 4 cm would be staged as T2. A single, 2.5-cm, mobile node would stage this tumor as N1. Oral Cavity and Oropharynx: T1 Tumor ≤ 2 cm T2 Tumor \> 2 but \< 4 cm T3 Tumor \> 4 cm T4 Tumor invades adjacent structures, such as cortical bone, tongue, skin, or soft tissue of the neck N1 One ipsilateral node: \< 3 cm N2a One ipsilateral node: \> 3 but ≤ 6 cm N2b Multiple ipsilateral nodes: ≤ 6 cm N2c Bilateral contralateral nodes: ≤ 6 cm N3 Any nodes \> 6 cm

Answer 87

The correct response is Option E. Following viral illness, Bell palsy is by far the most common form of unilateral facial paralysis. A period of three weeks should be allowed for observation before an extensive work up is initiated. Electromyography characterizes muscle activity but requires an interval of 14 to 21 days following paralysis before accurate results are possible. This is most useful in determining late prognosis in complete nerve paralysis. MRI is highly accurate in identifying mass lesions of other defects along neural pathways. In association with recent viral illness, this young, healthy individual is unlikely to demonstrate neoplasia relative to his risk for Bell palsy. Nerve excitability testing measures the membrane polarization, ion channel function, and paranodal/internodal condition of peripheral nerves. This technique is helpful in characterizing a wide variety of neuromuscular disorders, including multifocal motor neuropathy, conduction block in carpal tunnel syndrome, and diabetic neuropathy. Still, an observation period of three weeks is appropriate before testing is requested. Schirmer test uses paper strips inserted into the eye for several minutes to measure the production of tears. More than 10 mm of moisture on the filter paper in five minutes is a normal test result.

Answer 88

The correct response is Option C. Salivary leaks usually occur in a delayed fashion hallmarked by fullness in the neck, erythema, increased white blood count, and sometimes fever. In addition, early signs of a leak can be seen in the patient €™s drains, with brown discoloration and turbid changes of the fluid output with multiple air bubbles. Later stages of the leak usually cause a wound breakdown and ultimately a true pharyngocutaneous fistula. This problem can cause (a) a delay in further postoperative treatment, eg, radiation therapy, (b) a delay in feeding the patient and create the need for total parenteral nutrition or a gastric feeding tube, and (c) an arterial blowout and fatality, especially when there is no muscle coverage over the carotid artery. It is incumbent on all reconstructive surgeons to work with their extirpative colleagues to have a high suspicion for such a problem, especially in pharyngeal reconstruction. Early intervention, such as opening the wound (to prevent bathing of the carotid artery in saliva) and packing are the basic tenets of care. If, however, the carotid artery is exposed and in danger or postoperative radiation will be delayed beyond an oncologically safe time point, further reconstruction with a pedicled flap, usually a pectoralis major, is performed to potentially close the fistula but, more importantly, to cover the carotid artery. Many radiation oncologists will offer treatment even if there is a fistula as long as the major sources of danger have been overcome. Hematomas and chyle leaks are usually apparent earlier than five days. A chyle leak becomes even more obvious by changes in the quantity and quality of the drainage after any initiation of feeding. Seromas can occur at any time, but in the scenario described, would be less likely and are usually seen later in the postoperative course. Although scenarios where a working internal Doppler and a dying flap could be proposed, they are very unlikely and the machine €™s primary importance is for monitoring buried flaps. Many times surgeons will design a €œmonitoring € paddle to be externalized, obviating the need for an internal Doppler.

Answer 89

A radial forearm free flap is the most appropriate reconstructive option for the patient described. A dorsal tongue flap would be difficult to inset in the floor of the mouth and would create additional tethering. A large defect of the floor of the mouth with a marginal mandibulectomy would be difficult to close with a local flap in a patient who has undergone radiation. An osteocutaneous fibular free flap is inappropriate because there is no segmental mandibular defect with a marginal mandibulectomy. A split-thickness skin graft would be inappropriate to place on exposed bone.

Answer 90

The correct response is Option A. The patient described has SjÃ¶gren syndrome. This syndrome consists of xerostomia and keratoconjunctivitis sicca, resulting from lymphocyte-mediated destruction of salivary and lacrimal glands. SjÃ¶gren syndrome is caused by an autoimmune process that may be primary, or the syndrome may be a specific expression of another systemic autoimmune disease. In the secondary form, other organs may be involved, with conditions such as scleroderma, biliary cirrhosis, rhinitis, obstructive pulmonary disease, vasculitis, myositis, rheumatoid arthritis, and anemia. In the primary form, there is an increased risk of lymphoma (6% to 7%), but neither form has increased risk of salivary gland malignancies. Biopsy of the labial salivary gland remains the diagnostic method of choice for SjÃ¶gren syndrome, although sialochemical studies, scintigraphy, contrast sialography, and flow rate analysis have also been used. Serologic tests of value include rheumatoid factor, ANA, SS-A, and SS-B. Immunogenetic typing is also of value, including HLA-DR4, HLA-B8, and HLA-DR3. Fine-needle aspiration is most valuable when it yields malignant cells in cases of salivary gland malignancy; however, it would fail to show a specific cellular pattern of focal periductal lymphocytic infiltrate and acinar degeneration as is typical in SjÃ¶gren syndrome. Furthermore, these findings are seen equally in biopsies of parotid, submandibular, and minor salivary gland tissue, with the latter being the least invasive method. MRI and CT are of greater value in identifying neoplasms, not inflammatory conditions. The only imaging studies used in the diagnosis of SjÃ¶gren syndrome are scintigraphy, which shows major salivary gland dysfunction, and contrast sialography, which shows filling defects and punctate sialectasia. However, these findings are nonspecific. An elevated level of angiotensin-converting enzyme is a positive serologic finding in sarcoidosis affecting the parotid gland and the eye (Heerfordt syndrome), not in SjÃ¶gren syndrome. Superficial parotidectomy would certainly render tissue for biopsy but is unnecessary when less invasive techniques are available. Furthermore, the treatment of SjÃ¶gren syndrome is medical, not surgical.

Answer 91

The correct response is Option A. This malignancy is the second or third (depending on the study) most common in the parotid gland after mucoepidermoid carcinoma. Facial weakness combined with pain to touch of a mass anywhere in the parotid gland, which may extend well below the ear and into the buccal space, is a salivary malignancy until proven otherwise. Adenoid cystic carcinoma is well known for its neurotropism, and concomitant findings of weakness of the facial nerve and pain in the distribution on cranial nerve V are not uncommon. Adenoid cystic carcinoma is one of the most common malignancies of the submandibular and minor salivary glands. Facial nerve involvement is a significant poor prognostic indicator in any location. Pleomorphic adenoma and Warthin tumor are benign lesions not associated with pain and weakness of the facial nerve. Likewise, lymphoma, a more rare tumor of the parotid gland, is not associated with facial nerve involvement. Lymphoma is usually associated with various collagen connective diseases, such as SjÃ¶gren syndrome. Metastatic jugular nodes, which become very large, can be locally destructive. These are usually fast growing and associated with a primary lesion with all of its related morbidity, eg, dysphagia and dysphonia.

Answer 92

The correct response is Option E. Salivary gland tumors frequently occur within the parotid gland, and the vast majority (75%) of parotid tumors are benign. Warthin tumor is a common neoplasm of the parotid gland, accounting for 10% of all parotid tumors. These tumors are usually painless and tend to grow very slowly, frequently over several years. They are more common in older men and are frequently bilateral. Warthin tumors are usually treated with superficial parotidectomy with only minimal margins needed. Recurrence is common. Adenocarcinomas comprise 10% of malignant parotid gland tumors. These tumors vary according to grade and histologic appearance. They most frequently occur after the fifth decade of life and commonly involve the minor salivary glands. In the parotid gland, they manifest as fixed masses characterized by occasional pain or facial palsy. Adenocystic carcinoma, or cylindroma, is infrequent in the parotid gland (7%) but quite common in the minor salivary glands (35%). It is a slowly growing mass, often associated with pain and facial palsy. These tumors are aggressive, with one-third to one-half of affected patients developing metastatic disease. Mucoepidermoid carcinoma is the most common malignancy of the parotid gland. It is rarely bilateral. It may be low or high grade. Low-grade tumors are slow-growing and indolent; high-grade tumors are much more aggressive. The recurrence rate of high-grade tumors is increased, and the facial nerve is frequently affected. Pleomorphic adenomas, or benign mixed tumors, are the most common salivary gland neoplasms, comprising about 60% of all salivary gland tumors and 80% of benign tumors. They occur as painless salivary masses that are firm and well circumscribed. Facial weakness is not found. Bilateral tumors are rare. This tumor is treated by resection and in rare cases (recurrence) can transform into malignant mixed tumor.

Answer 93

The correct response is Option A. The patient described is set to undergo a right mandibular resection and right neck dissection. The simplest method of reconstruction is a right (ipsilateral to the recipient vessels) osteocutaneous fibula flap. This flap results in optimal placement of the pedicle vessels for microvascular anastomosis. Unless osseous flaps are unavailable, a rectus flap with reconstruction plate should be avoided because of the high incidence of plate exposure after external beam radiation therapy. A radial forearm flap would not provide adequate bone length for reconstruction of the defect described. Similarly, an osteocutaneous scapular flap lacks adequate bone stock for repair of such an extensive defect.

Answer 94

The correct response is Option D. Tumors of the oral cavity and oropharynx are staged according to the TNM (tumor, node, metastasis) system. The mobile tongue (anterior to the circumvallate papillae) is part of the oral cavity, whereas the base of the tongue is part of the oropharynx. A tumor with dimensions greater than 2 cm but less than 4 cm is stage T2. A single, 4-cm, mobile node is stage N2a. Oral cavity and oropharynx: T1 Tumor \<2 cm T2 Tumor \>2 but \<4 cm T3 Tumor \>4 cm T4 Tumor invades adjacent structures, such as cortical bone, tongue, skin, or soft tissue of the neck N1 One ipsilateral node: \<3 cm N2a One ipsilateral node: \>3 but \<6 cm N2b Multiple ipsilateral nodes: \<6 cm N2c Bilateral contralateral nodes: \<6 cm N3 Any nodes \>6 cm M0 No distant metastases M1 Presence of distant metastases

Answer 95

The correct response is Option D. The parotid gland is the most common site for salivary gland tumors. Approximately 70% of salivary gland tumors occur in the parotid gland; approximately 75% of all parotid tumors are benign, and the remainder are malignant. The most common benign tumor of the parotid is a pleomorphic adenoma. The most common malignant neoplasm of the parotid gland for both adults and children is mucoepidermoid carcinoma (29.3% to 43.5% of all malignant salivary gland tumors). The histology of mucoepidermoid carcinoma may include both epithelial cells and mucinous cells, but, with higher histologic grades, the presence of mucinous cells is scant or absent. The incidence of other salivary gland malignancies, such as adenocarcinoma (14%), adenoid cystic carcinoma (20%), carcinoma expleomorphic adenoma (5%), and squamous cell carcinoma (8%), is less overwhelming and therefore statistically less likely.

Answer 96

The correct response is Option E. Treatment of cancer of the lip up to 2 cm with radiation therapy is very effective, reaching cure rates of 90% to 95%. These rates are similar to cure rates with surgical excision. With increased tumor burden, the success of radiotherapy lessens to 75% to 80% for T2 lesions and to 40% for T3 and T4 lesions with involvement of the regional lymph nodes. Radiation therapy should be discussed as an alternative treatment in patients with superficial lip cancer that spreads over more than one third of the lip, cancer that involves the commissure, or recurrent cancers, and in patients who are unable or unwilling to undergo surgery.

Answer 97

The correct response is Option B. Nasal dermoids, gliomas, and encephaloceles are congenital midline nasal lesions that share a similar embryopathogenesis. Early in development, a small fontanelle, the fonticulus frontalis, is briefly present between the frontal and nasal bones. A second prenasal space is seen at the same time between the nasal bones and the nasal cartilage. The prenasal space is referred to as the foramen cecum when it later becomes surrounded by bone. Inadequate closure of either the fonticulus frontalis or foramen cecum can lead to sinus tracts and/or dermoid formation in this region. Both gliomas and encephaloceles are ectodermal neural tissue of the brain that has remained in the area of the fonticulus frontalis or foramen cecum. Encephaloceles always maintain a connection to the cerebrospinal fluid and are differentiated from gliomas by the presence of a defect in the cranium that allows herniation to occur (as seen in the CT scan shown). If untreated, obstructive hydrocephalus would not cause an isolated frontoethmoid skull defect but would likely present with macrocephaly. A pediatric rhabdomyosarcoma of the orbit would more likely present as an invasive soft-tissue mass causing proptosis.

Answer 98

The correct response is Option D. The surgical management of an ameloblastoma is controversial. Treatment modalities include cryotherapy, curettage, enucleation, or segmental resection and reconstruction. There are three main types of ameloblastomas: peripheral, unicystic, and multicystic tumors. Peripheral tumors are odontogenic in origin and have histologic characteristics consistent with intraosseous ameloblastomas. However, they occur in the soft tissues covering the tooth-bearing parts of the jaw. These peripheral tumors can be treated with local excision. Unicystic ameloblastomas can be treated conservatively with enucleation because they appear clinically as a cyst. When the tumor involves the periphery of the connective tissue wall of the cyst, a peripheral ostectomy should be considered. Multicystic ameloblastomas or large ameloblastomas that involve the surrounding of the bone and extend into the soft tissues are locally aggressive and should be treated with segmental resection and reconstruction.

Answer 99

The correct response is Option D. According to the American Joint Committee on Cancer (AJCC) TNM staging, if a tumor invades the mandible through the cortical bone, it is, by definition, a stage IV tumor regardless of size. In this case, considering that there is one node less than 3 cm on the ipsilateral side, the appropriate staging of this tumor is IVA. Stage II and III tumors do not involve invasion of the mandible or adjacent structures. Stage IVB involves metastasis to a lymph node more than 6 cm in greatest dimension. Stage IVC involves distant metastasis. Oral Cavity: T1 Tumor \<2 cm T2 Tumor \>2 but \<4 cm T3 Tumor \>4 cm T4 Tumor invades adjacent structures such as cortical bone, tongue, skin, or soft tissues of the neck N1 One ipsilateral node \<3 cm N2a One ipsilateral node \>3 and \<6 cm N2b Multiple ipsilateral nodes \<6 cm N2c Bilateral contralateral nodes \<6 cm N3 Any nodes \>6 cm M0 No distal metastasis M1 Distal metastasis

Answer 100

The correct response is Option C. Based on the operative findings, this mass is a glioma. A congenital midline nasal mass is most likely to be a dermoid cyst, an encephalocele, or a glioma. Diagnosis can be facilitated by preoperative imaging studies. A dermoid cyst, which is the most common congenital nasal mass, typically contains sebaceous material and may communicate with the intracranial space. An encephalocele, which is a protrusion of the brain through an embryologic defect in the skull, is always covered by the dura. However, the content of the dural sac may vary. Gliomas consist of glial neural tissue and are not surrounded by dura. However, they may maintain a connection to it. Gliomas require thorough resection because of the risk of recurrence. A neurilemoma or neurofibroma is not likely to arise as a midline nasal mass in a 6-month-old infant.

Answer 101

The correct response is Option C. Based on the operative findings, this mass is a glioma. A congenital midline nasal mass is most likely to be a dermoid cyst, an encephalocele, or a glioma. Diagnosis can be facilitated by preoperative imaging studies. A dermoid cyst, which is the most common congenital nasal mass, typically contains sebaceous material and may communicate with the intracranial space. An encephalocele, which is a protrusion of the brain through an embryologic defect in the skull, is always covered by the dura. However, the content of the dural sac may vary. Gliomas consist of glial neural tissue and are not surrounded by dura. However, they may maintain a connection to it. Gliomas require thorough resection because of the risk of recurrence. A neurilemoma or neurofibroma is not likely to arise as a midline nasal mass in a 6-month-old infant.

Answer 102

The correct response is Option D. The surgical management of an ameloblastoma is controversial. Treatment modalities include cryotherapy, curettage, enucleation, or segmental resection and reconstruction. There are three main types of ameloblastomas: peripheral, unicystic, and multicystic tumors. Peripheral tumors are odontogenic in origin and have histologic characteristics consistent with intraosseous ameloblastomas. However, they occur in the soft tissues covering the tooth-bearing parts of the jaw. These peripheral tumors can be treated with local excision. Unicystic ameloblastomas can be treated conservatively with enucleation because they appear clinically as a cyst. When the tumor involves the periphery of the connective tissue wall of the cyst, a peripheral ostectomy should be considered. Multicystic ameloblastomas or large ameloblastomas that involve the surrounding of the bone and extend into the soft tissues are locally aggressive and should be treated with segmental resection and reconstruction.

Answer 103

The correct response is Option D. According to the American Joint Committee on Cancer (AJCC) TNM staging, if a tumor invades the mandible through the cortical bone, it is, by definition, a stage IV tumor regardless of size. In this case, considering that there is one node less than 3 cm on the ipsilateral side, the appropriate staging of this tumor is IVA. Stage II and III tumors do not involve invasion of the mandible or adjacent structures. Stage IVB involves metastasis to a lymph node more than 6 cm in greatest dimension. Stage IVC involves distant metastasis. Oral Cavity: T1 Tumor \<2 cm T2 Tumor \>2 but \<4 cm T3 Tumor \>4 cm T4 Tumor invades adjacent structures such as cortical bone, tongue, skin, or soft tissues of the neck N1 One ipsilateral node \<3 cm N2a One ipsilateral node \>3 and \<6 cm N2b Multiple ipsilateral nodes \<6 cm N2c Bilateral contralateral nodes \<6 cm N3 Any nodes \>6 cm M0 No distal metastasis M1 Distal metastasis

Answer 104

The correct response is Option B. Nasal dermoids, gliomas, and encephaloceles are congenital midline nasal lesions that share a similar embryopathogenesis. Early in development, a small fontanelle, the fonticulus frontalis, is briefly present between the frontal and nasal bones. A second prenasal space is seen at the same time between the nasal bones and the nasal cartilage. The prenasal space is referred to as the foramen cecum when it later becomes surrounded by bone. Inadequate closure of either the fonticulus frontalis or foramen cecum can lead to sinus tracts and/or dermoid formation in this region. Both gliomas and encephaloceles are ectodermal neural tissue of the brain that has remained in the area of the fonticulus frontalis or foramen cecum. Encephaloceles always maintain a connection to the cerebrospinal fluid and are differentiated from gliomas by the presence of a defect in the cranium that allows herniation to occur (as seen in the CT scan shown). If untreated, obstructive hydrocephalus would not cause an isolated frontoethmoid skull defect but would likely present with macrocephaly. A pediatric rhabdomyosarcoma of the orbit would more likely present as an invasive soft-tissue mass causing proptosis.

Answer 105

The correct response is Option B. Among salivary gland hemangiomas, 90% arise in the parotid gland. The remaining 10% arise in the minor salivary gland, sublingual gland, or submandibular gland. Parotid hemangiomas typically affect four times as many female patients as male patients. About 25% of parotid hemangiomas are bilateral, and about 50% of affected patients have a cutaneous lesion at birth. Parotid hemangiomas often ulcerate during the early proliferative phase and typically involve nearby structures, including the ear, lip, subglottal region, eye, and nose. Pharmacotherapy with corticosteroids, interferon, or both is effective in most infants with parotid hemangioma. Surgical treatment is reserved for patients who do not respond to pharmacologic management and for those who require reconstruction during the involutional phase. Occasionally, patients require tracheostomy for management of airway complications. In one study, 30% of patients with parotid hemangioma did not require medical or surgical intervention.

Answer 106

The correct response is Option E. Multinodular local tumors are the most common form of recurrence in patients with previously removed pleomorphic adenomas, and the most appropriate management of these tumors is radical resection followed by radiation therapy. The extent of resection depends on the nature of the recurrence and the extent of the previous surgery; however, the facial nerve should be preserved if possible. If the facial nerve cannot be preserved, immediate reconstruction with a nerve graft is indicated. In addition, radiation therapy has been shown to result in a marked decrease in the risk for multinodular recurrence in patients with parotid gland tumors when compared with surgery alone. Chemotherapy is not used for treatment of multinodular local recurrent pleomorphic adenomas. Cryotherapy is recommended for control of nonresectable hepatic tumors. Hormone therapy and immunotherapy are not appropriate management options in patients with parotid gland tumors.

Answer 107

The correct response is Option C. The most likely diagnosis in this patient is pleomorphic adenoma, or mixed tumor. This is the most common benign tumor of the parotid gland, comprising 65% of all salivary gland neoplasms, 55% of all parotid masses, and 80% of all benign parotid tumors. Most pleomorphic adenomas arise from within the superficial lobe of the gland; only 10% are located deep to the facial nerve. These encapsulated tumors contain both epithelial and mesenchymal elements within a stroma, which can vary from mucoid to myxoid to chondroid. Because small lobules of cells may extend beyond the capsule, simple enucleation frequently results in tumor recurrence. Therefore, appropriate management is superficial lobe parotidectomy with preservation of the facial nerve. Basal cell adenoma is the most common type of monomorphic adenoma found in the minor salivary glands of the upper lip. These tumors rarely occur in the parotid gland. Histologic examination is most likely to show rows of palisading cells with a thickened basement membrane. Myoepithelioma is a well-circumscribed benign tumor that arises from myoepithelial cells. This tumor is rare and typically affects the parotid gland or palate. Although it is clinically similar to pleomorphic adenoma, histologic examination shows spindle cells. Sjögren’s syndrome is an autoimmune disease occurring most frequently in women and is characterized by destruction of the exocrine glands due to immune-related mechanisms. When associated with rheumatoid arthritis, it is known as secondary Sjögren’s syndrome. Unilateral or bilateral salivary gland swelling, frequently affecting the parotid gland, is present in 80% of patients with primary Sjögren’s syndrome and 40% of patients with secondary disease. Additional distinguishing findings include xerostomia, interstitial pneumonitis, Raynaud’s phenomenon, lymphadenopathy, purpura, pancreatitis, renal disease, and recurrent parotitis. Warthin tumor, or papillary cystadenoma lymphomatosum, is a slow-growing multicystic mass most frequently seen in men between the ages of 40 and 70 years. It is almost always localized to the parotid gland and rarely occurs in the submandibular gland. Warthin tumors comprise 10% of all parotid tumors; 10% of affected patients have multicentric lesions, while another 10% have bilateral findings. Histologic examination shows a papillary epithelium containing lymphoid stroma that projects into cystic spaces.

Answer 108

The correct response is Option D. The staging of squamous cell carcinomas of the lip involves three descriptors: T, N, and M. The T descriptor is based on the diameter or surface area of the tumor. The N descriptor describes nodal status. The M descriptor indicates distance of metastasis beyond the neck. This staging criteria allows physicians to predict patient outcomes and to choose appropriate therapy based on comparisons with patients in large studies. In this patient who has a 2.2 \* 1.5-cm squamous cell carcinoma of the right lower lip with involvement of one lymph node only, the tumor is correctly classified as T4 N1 M0. Although the tumor can be classified as T2 based on size alone, any tumor that involves infiltration of skeletal muscle, nerve, cartilage, or bone (ie, extradermal structures) is classified as T4. Metastasis to one regional lymph node is N1, and absence of distant metastases is M0. Any T4 lesion is classified as Stage IV; a tumor with lesser T classification combined with an N1 would be designated as Stage III. A TNM classification table is shown below. Status of Tumor (T) TX - Primary tumor cannot be assessed T0 - No evidence of primary tumor Tis - Carcinoma in situ T1 - Tumor 2 cm or less in greatest dimension T2 - Tumor more than 2 cm but not more than 4 cm in greatest dimension T3 - Tumor more than 4 cm in greatest dimension T4 (lip) - Tumor invades adjacent structures (eg, through cortical bone, inferior alveolar nerve, floor of mouth, skin of face) T4 (oral cavity) - Tumor invades adjacent structures (eg, through cortical bone, into deep [extrinsic] muscle of tongue, maxillary sinus, skin. Superficial erosion alone of bone/tooth socket by gingival primary tumor is not sufficient to classify as T4). Stages of Lymph Nodes (N) NX - Regional lymph nodes cannot be assessed N0 - No regional lymph node metastasis N1 - Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2 - Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimensions; or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N2a - Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension N2b - Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension N2c - Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension Status of Metastasis (M) MX - Distant metastasis cannot be assessed M0 - No distant metastasis M1 - Distant metastasis

Answer 109

The correct response is Option D. Chronic exposure to nickel has been shown to be associated with the development of squamous cell carcinoma of the nasal sinuses. This is the most common malignancy of the sinonasal tract, affecting the maxillary sinus most frequently, followed by the nasal sinus cavity, ethmoid sinus, and sphenoid sinus. In one study, workers at a nickel refinery in Norway developed squamous cell carcinoma at 250 times the expected rate, with a latent period varying from 18 to 36 years. Exposure to alcohol and tobacco has been associated with squamous cell carcinoma of the upper aerodigestive tract, not the sinonasal tract. Exposure to asbestos has been shown to increase the risk for development of pleural mesothelioma, and benzene exposure is associated with the development of hemopoietic malignancies.

Answer 110

The correct response is Option A. This 38-year-old woman with gustatory sweating has findings consistent with Frey syndrome, a condition that occurs in more than 50% of patients who have undergone parotidectomy. Frey syndrome is thought to be caused by the development of anastomoses between postganglionic parasympathetic fibers from the otic ganglion, which are carried by the auriculotemporal nerve, and postganglionic sympathetic fibers in the sweat glands that lie within the vascular plexus of the skin. The fibers of both systems are cholinergic and mediated by acetylcholine. The Minor starch-iodine test can be used to establish a diagnosis of Frey syndrome in symptomatic patients. In this test, 10% povidone-iodine is applied to the cheek, allowed to dry, and covered with cornstarch. Following the administration of a lemon drop stimulus, a region of blue discoloration will elicit the location of the gustatory sweating. Intracutaneous botulinum toxin, which relieves the hyperhidrosis and flushing associated with Frey syndrome by blocking neurotransmission of acetylcholine, can be administered to confirm the diagnosis. Although one series of botulinum toxin injections may result in relief of symptoms for as long as one year, repeat injections are frequently required. Appropriate operative management is direct excision of involved skin and interposition of any one of a number of autologous tissues, including sternocleidomastoid muscle, fascia lata, lyophilized human dura, a SMAS flap, or a dermal graft between the skin and the parotid gland. Human preserved dermal allograft has been used recently with some success for interposition grafting. The chorda tympani mediates taste sensation to the anterior two-thirds of the tongue via the facial (VII) nerve, which innervates the muscles of facial expression. The infraalveolar nerve provides sensation to the teeth, while the lingual nerve provides sensation to the tongue.

Answer 111

The correct response is Option D. In patients who have been previously diagnosed with squamous cell carcinoma but who continue to smoke, the incidence of metachronous carcinoma is 30% to 40%. In contrast, patients diagnosed with squamous cell carcinoma who stop smoking have only a 6% risk for development of metachronous carcinoma. The prevalence of metachronous carcinoma in all patients who have squamous cell carcinomas affecting a second site, regardless of smoking history and/or continued exposure to tobacco, is reported as 14.2%. The incidence of synchronous carcinomas has been reported as 5% to 7%. Further studies of tumor biology will continue to delineate the effects of carcinogens such as tobacco on the mucosal surfaces of the upper aerodigestive tract.

Answer 112

The correct response is Option D. The safest and most convenient way to identify the facial nerve trunk during a parotidectomy procedure involves the use of the tympanomastoid suture as a landmark. This structure is defined as the suture line located between the posterior bony auditory canal and the mastoid portion of the temporal bone. The facial nerve can be found at a point 6 mm to 8 mm below the inferior end of the tympanomastoid suture line. If the region of the suture line is carefully dissected (ie, with a fine hemostat) in the direction of the facial nerve, the soft tissues can then be separated to reveal the glistening, white facial nerve. Identification and dissection of the temporal branches of the facial nerve is a difficult, dangerous procedure; tagging of the distal branches is instead more reliable. With this technique, the surgeon identifies the marginal mandibular nerve as it crosses the facial vein and then performs a retrograde dissection to the nerve trunk. Because the earlobe is not a fixed point, it cannot be used as a landmark. A tragal pointer, which is defined as the cartilaginous portion of the external auditory canal at its bony junction with the skull, is used instead. The facial nerve can be found within 5 mm from this point as it exits the stylomastoid foramen. The plane between the superficial and deep lobes of the parotid gland is obscure; a proximal approach is safer and more effective. Nerve stimulators are used as aids and are not the primary means for identifying the nerve trunk.

Answer 113

The correct response is Option C. Pleomorphic adenoma is most appropriately managed with superficial parotidectomy. A pleomorphic adenoma is an isolated, firm, round tumor surrounded by a delicate capsule. It is the most common benign tumor of the salivary glands and is rarely associated with malignant transformation. Approximately 90% of pleomorphic adenomas affecting the parotid gland lie superficial to the facial nerve. Because pleomorphic adenomas are characterized by microscopic extension of tumor through the capsule, and thus associated with a multifocal pattern of recurrence, superficial parotidectomy with preservation of the facial nerve is indicated. Observation and/or simple reexcision are inadequate management and are likely to result in recurrence. Lymph node dissection is an unnecessary, excessive procedure in a patient with a benign tumor. Total parotidectomy is also excessive and can lead to serious morbidity resulting from injury or sacrifice of the facial nerve.

Answer 114

The correct response is Option A. Gustatory sweating that develops following parotidectomy is known as Frey's syndrome or auriculotemporal syndrome and results from abnormal regeneration of auriculotemporal nerve fibers to sweat glands within the skin. Placement of thin surgical flaps over the parotid gland has been shown to exacerbate this condition; interposition of a submuscular aponeurotic system (SMAS) flap between the parotid bed and overlying skin may lead to improvement. The diagnosis can be confirmed by placing a single-ply facial tissue on the skin overlying the parotid gland; damp patches will be seen in areas affected by gustatory sweating. The Minor starch-iodine test, which involves placement of a 1 ( 1-cm test tape (containing iodine and starch) on the affected area, can be used to determine the total number of damp patches and thus confirm the distribution of the diaphoresis. Although skin excision alone can successfully treat Frey's syndrome, tympanic neurectomy may be required. Systemic administration of anticholinergic agents results in abatement of symptoms but is associated with adverse effects and thus not recommended by many physicians. Topical glycopyrrolate (Robinul) or diphemanil methyl sulfate (Prantal) can be applied to the affected area to control gustatory sweating. When the diaphoresis has subsided, topical 20% aluminum chloride in alcohol (Drysol) should be applied once daily.

Answer 115

The correct response is Option C. In this patient who has a 2.5-cm squamous cell carcinoma of the tongue with involvement of one lymph node only, the tumor is correctly classified as T2 N1 M0. The staging of squamous cell carcinomas of the lip involves three descriptors: T, N, and M. The T descriptor is based on the diameter or surface area of the tumor. The N descriptor describes nodal status. The M descriptor indicates distance of metastasis beyond the neck. This staging criteria allows physicians to predict patient outcomes and choose appropriate therapy based on comparisons with patients in large studies. A TNM classification table is shown on page below. Status of Tumor (T) TX - Primary tumor cannot be assessed T0 - No evidence of primary tumor Tis - Carcinoma in situ T1 - Tumor 2 cm or less in greatest dimension T2 - Tumor more than 2 cm but not more than 4 cm in greatest dimension T3 - Tumor more than 4 cm in greatest dimension T4 (lip) - Tumor invades adjacent structures (eg, through cortical bone, inferior alveolar nerve, floor of mouth, skin of face) T4 (oral cavity) - Tumor invades adjacent structures (eg, through cortical bone, into deep [extrinsic] muscle of tongue, maxillary sinus, skin. Superficial erosion alone of bone/tooth socket by gingival primary tumor is not sufficient to classify as T4). Stages of Lymph Nodes (N) NX - Regional lymph nodes cannot be assessed N0 - No regional lymph node metastasis N1 - Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2 - Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimensions; or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N2a - Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension N2b - Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension N2c - Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension Status of Metastasis (M) MX - Distant metastasis cannot be assessed M0 - No distant metastasis M1 - Distant metastasis In order to determine the correct clinical staging of this type of tumor, the surgeon must first examine the primary lesion and the lymph nodes in the neck. A CT scan should be obtained to rule out potential invasion of adjacent structures; histologic evaluation of a biopsy specimen of the lesion will best establish and/or confirm the diagnosis. Further evaluation to determine the extent of metastases will include a radiograph of the chest, complete blood cell count, and blood chemistry studies. If the patient's symptoms are applicable to specific organ systems, other diagnostic tests may be required.

Answer 116

The correct response is Option A. Reconstruction of the anterior mandible is best accomplished with the fibula osteocutaneous free flap. This flap provides excellent bone quality and a segmental blood supply, which allows for multiple osteotomies. This is crucial because successful reconstruction of the anterior mandible will require a minimum of two osteotomies in order to restore the contour of the mandibular arch. Pectoralis major flaps with attached rib have been shown to be inadequate for mandibular reconstruction because of the poor quality of bone and difficulties with orientation. In addition, reconstruction plates are especially susceptible to fracture and exposure when used in the anterior mandible. Although the radial forearm flap provides excellent soft tissue for replacement of intraoral lining, only a limited amount of bone can be harvested, and osteotomies are poorly tolerated. Bone grafts are useful for reconstruction of defects less than 3 cm in patients who will not be undergoing radiation therapy.

Answer 117

The correct response is Option C. Although squamous cell carcinoma rarely affects the paranasal regions, 80% of tumors that do appear in this region arise within the maxillary sinus. The ethmoid, frontal, and sphenoid sinuses are affected less frequently. Approximately 3% of malignancies involving the upper aerodigestive tract are found within the nasal and paranasal regions. Furthermore, approximately 70% of malignant tumors seen in this region are squamous cell carcinomas; this frequency is thought to be related to exposure to nickel and other chemicals. The nasal floor is typically not associated with the development of malignancy but can be affected as a result of direct tumor extension, as many tumors are asymptomatic and thus remain undiagnosed while enlarging and advancing locally.

Answer 118

The correct response is Option C. This patient who has a squamous cell carcinoma of the lip should undergo surgical excision of the lesion with bilateral supraomohyoid neck dissection and marginal mandibulectomy. A 4.5-cm tumor of the lower lip with extension into the mandible but without palpable nodes in the neck is classified as T3 N0 M0. One study of patients with squamous cell carcinoma reported neck metastases in 63% of patients with T3 lesions; therefore, selective neck dissection is warranted. Marginal mandibulectomy is also appropriate in this patient who has tumor extension, but not invasion, into the mandible. Segmental mandibulectomy is not required because the tumor has not invaded the mandible. Adjuvant chemotherapy is not recommended for patients with squamous cell carcinoma of the lip. Radiation therapy alone may be an option in patients with N0 tumors who are at increased risk for metastases or in patients who are poor surgical candidates, but radiation therapy is not used in combination with chemotherapy.

Answer 119

The correct response is Option E. The most appropriate management of this patient's Merkel cell carcinoma is excision with 3-cm margins followed by superficial parotidectomy and ipsilateral neck dissection. Merkel cell carcinoma is a rare cutaneous malignancy believed to arise from neuroendocrine cells within the skin. It typically occurs on the head, neck, and other sun-exposed areas in patients 50 to 70 years of age. Lymphatic and distant metastasis are common, and prognosis is poor; mortality rates as high as 67% have been reported. Excision of the tumor with margins of 2 to 5 cm is generally recommended; prophylactic neck dissection is advocated because approximately 50% of affected patients have positive regional nodes at the time of initial diagnosis. Because the parotid gland is a primary drainage basin for preauricular lesions, superficial parotidectomy should also be performed. Although radiation therapy can be performed adjuvantly, it is inadequate when used with excision alone.

Answer 120

The correct response is Option D. In this patient who has a 2.5-cm squamous cell carcinoma of the lateral floor of the mouth that is adherent to the adjacent mandible, as well as a 2-cm palpable lymph node but no evidence of distant metastases, the tumor is correctly classified as T4 N1 M0. The staging of squamous cell carcinomas of the oral cavity involves three descriptors: T, N, and M. The T descriptor is based on the diameter or surface area of the primary tumor. The N descriptor describes nodal status. The M descriptor indicates distance of metastasis beyond the neck. This staging criteria allows physicians to predict patient outcomes and choose appropriate therapy based on comparisons with patients in large studies. A TNM classification table for squamous cell carcinoma of the oral cavity is shown below. Status of Tumor (T) TX - Primary tumor cannot be assessed T0 - No evidence of primary tumor Tis - Carcinoma in situ T1 - Tumor 2 cm or less in greatest dimension T2 - Tumor more than 2 cm but not more than 4 cm in greatest dimension T3 - Tumor more than 4 cm in greatest dimension T4 (lip) - Tumor invades adjacent structures (eg, through cortical bone, inferior alveolar nerve, floor of mouth, skin of face) T4 - (oral cavity) Tumor invades adjacent structures (eg, through cortical bone, into deep [extrinsic] muscle of tongue, maxillary sinus, skin; superficial erosion alone of bone/tooth socket by a gingival primary tumor is not sufficient to classify as T4) Status of Lymph Nodes (N) NX - Regional lymph nodes cannot be assessed N0 - No regional lymph node metastasis N1 - Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2 - Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension; or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N2a - Metastasis in a single ipsilateral lymph node more than 3 cm but not more than 6 cm in greatest dimension N2b - Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension N2c - Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N3 - Metastasis in a single ipsilateral lymph node more than 6 cm in greatest dimension Status of Metastasis (M) MX - Distant metastasis cannot be assessed M0 -No distant metastasis M1 - Distant metastasis

Answer 121

The correct response is Option E. Radical excision remains the recommended primary treatment method for patients with osteogenic sarcoma, which is an aggressive, rapidly expanding mass often seen in the maxilla or mandible. However, adjuvant chemotherapy and radiation therapy have also been recommended as of late; clinical randomized trials of patients with osteogenic sarcoma have shown improved disease-free survival rates following chemotherapy and radiation therapy in patients with tumors affecting either the head and neck or the extremities. In addition, combination therapy is recommended because these tumors recur frequently. The mean age of onset of osteogenic sarcoma is age 31 years; symptoms at initial presentation include jaw pain and loosening of teeth. Risk factors include fibrous dysplasia and retinoblastoma, as well as previous exposure to ionizing radiation or colloidal thorium dioxide (Thorotrast). In patients who undergo surgical resection alone, five-year survival rates range from 23% to 35%.

Answer 122

The correct response is Option D. Approximately 9% of all salivary gland tumors originate within the minor salivary glands; the palate is the most common site of origin, with 50% of all minor gland tumors occurring here. In contrast, only 15% of all minor salivary gland tumors originate in the lip, 12% in the buccal mucosa, and 5% in both the tongue and floor of the mouth. Most minor salivary gland malignancies are classified histologically as adenoid cystic carcinomas, but other types can also be seen. The tumors affecting these glands are often smooth submucosal masses that are rarely associated with pain and numbness. Rapid tumor growth, pain, and ulceration are indicators of malignancy. Appropriate management of minor salivary gland tumors includes surgical resection with adequate margins, including any involved mucosa, muscle, or bone. Radiation therapy is recommended postoperatively for management of tumors with high-grade histologic features, positive surgical margins, perineural spread, deep invasion into muscle or bone, or lymph node metastasis.

Answer 123

The correct response is Option B. In this patient who has a chylous fistula, the most appropriate management is initiation of a medium-chain triglyceride diet and closed suction drainage of the neck. Chylous fistulas develop as a result of injury to the thoracic duct as it enters the jugular vein at the inferior region of the left neck; this finding is seen in as many as 4% of patients who have undergone radical neck dissection on the left. A medium-chain triglyceride diet will curb the flow of chyle into the region, while closed suction drainage will remove the existing chyle, allowing for closure of the fistula. Mediastinal exploration with ligation of the thoracic duct may be considered in patients who have refractory fistulas. Repair of the thoracic duct is generally not performed initially. Radiation therapy should only be considered after closure of the fistula. Although interposition of a pectoralis major myocutaneous flap may help to seal the fistula, it should not be considered as a first-line treatment.

Answer 124

The correct response is Option C. This patient has findings consistent with Merkel cell carcinoma, an extremely aggressive tumor most commonly encountered in the head and neck region of elderly women. These nodules are pink to deep purple in color and rarely ulcerate. Light microscopy will show dense sheets of oval cells with indistinct borders that invade the deep dermis, subcutaneous fat, and muscle while sparing the papillary dermis and epidermis. Some surgeons advocate the use of electron microscopy and immunohistochemistry because these lesions can be mistaken for metastatic oat cell carcinoma or poorly differentiated lymphoma. A biopsy specimen of the lesion will most likely stain positive for neuron-specific enolase. Because 33% of affected patients will experience a local recurrence within one year of initial treatment and approximately 50% will ultimately develop nodal metastases, wide local excision with a margin of 2.5 cm to 3 cm is indicated. En bloc resection of involved nodes and postoperative radiation therapy are also recommended; chemotherapy and prophylactic nodal dissection are controversial treatment options. Long-term survival rates are poor; only 55% of patients diagnosed with Merkel cell carcinoma will survive for three years. Factors that are associated with a poor prognosis include male gender, early age at initial onset, and location of the tumor on the head, neck, or trunk. Basal cell carcinomas are common slow growing tumors of the head and neck that can be pigmented or ulcerated. Because these tumors rarely metastasize, local excision with 5 mm margins is recommended. Malignant melanoma is a highly aggressive tumor of brown pigmentation that often develops within an existing nevus. Exposure to ultraviolet radiation has been associated. Melanomas of the hands and feet are associated with a significantly worse prognosis than those of the arm and leg. Excision with wide margins is advocated for treatment of malignant melanoma. Microcystic adnexal carcinomas are rare, flesh colored nodules involving the upper lip, nose, and periorbital regions in middle aged patients. Perineural invasion is almost always seen with this locally aggressive and often recurrent tumor. Ulceration and nodal metastases are rare. Appropriate management of microcystic adnexal carcinoma is Mohs' micrographic resection, including complete histologic examination of the tumor margins. Radiation therapy is ineffective. Squamous cell carcinomas arise from the malpighian layer and have a strong association with actinic radiation. Cutaneous squamous cell carcinomas have a rough, ulcerated appearance and most frequently affect the head and neck region. The overall rate of metastasis is extremely low. Direct excision or radiation therapy are equally advocated as initial treatment. Recurrent lesions are treated with Mohs' micrographic resection.

Answer 125

The correct response is Option D. Salivary gland tumors are characterized by diverse histologic appearances and variable biologic behavior. These tumors can be benign or malignant, and malignancies can be either primary or metastatic. It may also be difficult to distinguish between the different tumor types, especially on fine-needle aspiration. The rule of 80s regarding salivary gland tumors has been consistently backed up by the literature time and time again and describes the following: * 80% of all salivary gland tumors are in the parotid * 80% of parotid tumors are benign * 80% of the benign parotid tumors are pleomorphic adenomas Warthin tumor, myoepithelioma, and cystadenoma are all benign parotid gland tumors but occur at a lower frequency than pleomorphic adenomas. Mucoepidermoid carcinoma is the most common primary malignant tumor of the parotid and may appear similar to pleomorphic adenoma on CT scan.

Answer 126

The correct response is Option C. The patient has masseter hypertrophy and the gold standard study is CT/MRI. Plain x-rays would not be descriptive enough to confirm the diagnosis. Biopsy is invasive and not necessary to aid in clinical suspicion. Diagnosis is often made based on clinical examination, and further imaging may not be necessary. This is an issue with the soft tissue, and cephalometric analysis would not be appropriate for masseter hypertrophy.

Answer 127

The correct response is Option E. Maxillofacial prosthodontics is a specialized field of dentistry that deals with the rehabilitation of patients with defects or disabilities related to the head and neck. Common conditions that may require maxillofacial prosthodontics include congenital defects affecting the face, trauma or injury to the face, and head and neck cancer. Maxillofacial prostheses have multiple ways of attaching to the face, such as adhesives and osseointegrated implants. Titanium is used for osseointegrated implants, since they have a degree of biocompatibility that induces bone to integrate and provides a rigid bone anchor that allows abutments to exit the skin for attaching the prosthesis. Titanium is the most commonly used material for osseointegrated implants in maxillofacial prosthodontics. Glass, gold, aluminum, and iron are not commonly used in osseointegrated implants in maxillofacial prosthodontics.

Answer 128

The correct response is Option E. Traumatic optic neuropathy may result from direct injury to the optic (II) nerve or from traction on the globe that stretches the optic nerve during resection or reconstruction. Imaging is warranted to rule out impingement of the optic nerve by graft or hardware, which should be removed. High-dose corticosteroids are usually recommended. Prognosis for improvement is often poor. Entrapment of extraocular muscles from reconstruction can occur, but it is usually associated with diplopia secondary to restricted movement of the globe and sometimes pain from impingement of graft or hardware on the intraorbital soft tissues. Enophthalmos is not uncommon after extensive orbital wall resection but would not be associated with decreased vision. Similarly, orbital dystopia (eyes at different vertical levels) is not uncommon after extensive orbital wall resection. Usually, the globe is lower (hypophthalmos) on the affected side and may cause diplopia. Hardware exposure is usually not seen in the immediate setting after surgery and is unlikely to be associated with decreased vision in the acute setting.

Answer 129

The correct response is Option E. Chyle leak is a rare but difficult to manage complication following neck dissection. The leak may have also arisen from dissection of the transverse cervical artery and vein used in this case as recipient blood vessels for the anterolateral thigh free flap. The thoracic duct travels through the neck and terminates in the left internal jugular vein or the left subclavian vein in the supraclavicular region. There is also a right accessory lymphatic duct that can be injured during right neck dissection. Postoperative chyle leaks are usually identified after tube feeding is commenced. Laboratory analysis will show the presence of chylomicrons and a triglyceride concentration greater than 110 mg/dL. Multiple approaches to treatment have been recommended, including holding of feeds, use of total parenteral nutrition, or use of low-fat, medium-chain triglyceride (MCT) oral or tube feeds, since MCTs are not absorbed from the gut into the lymphatic system but instead are absorbed directly into the portal circulation. Octreotide is a long-acting somatostatin analogue and has also been used to reduce the formation of chyle. The proposed mechanism of action in the treatment of chyle leaks is decreasing absorption of triglycerides and inhibiting splanchnic circulation and gastrointestinal motility, all factors that affect lymph flow. Octreotide is given as a subcutaneous injection. Large leaks or those recalcitrant to conservative therapy are usually re-explored where the duct is identified and either repaired or ligated. In some cases, a flap such as the pectoralis major muscle pedicled flap is placed over the area of thoracic duct injury to help seal off any residual leakage. Sialogogues (such as chewing gum with sorbitol or xylitol), increased hydration, warm compresses, and massage are initial treatments used when the salivary gland duct is blocked. Glycopyrrolate can be used to help decrease salivary secretion when there is injury to the salivary gland causing a sialocele, such as after parotidectomy. Botulinum toxin type A injection is used to treat Frey syndrome and may be tried in salivary leaks as well. Antibiotics, such as amoxicillin with clavulanate, are usually given when a wound infection or fistula is a suspected cause of swelling. In this case, there is no erythema and drainage is consistent with chyle leak rather than an abscess or fistula.

Answer 130

The correct response is Option A. Polyetheretherketone (PEEK) is a polymer material that must be milled or three-dimensionally printed to create implantable alloplastic replacements for human bone. Because of this, PEEK cranioplasty implants are usually custom-made based on CT scan data to fix pre-existing defects. When used for immediate reconstruction, the implant may not precisely fit the defect, especially if the dimensions of the defect changed based on intraoperative findings. While PEEK implants that are too big may be reduced with a cutting bur, implants that are too small cannot be adjusted to fit the calvarial defect. Advantages of PEEK include its radiolucency, strength, light weight, and stiffness similar to bone, which minimizes stress shielding. Titanium mesh causes significant artifacts on radiographic images, which may interfere with tumor surveillance. Calcium hydroxyapatite cements have a tendency to be brittle and fracture. Methylmethacrylate is applied in a paste form and the curing process is exothermic, requiring continuous irrigation to prevent burning of the surrounding tissues. Autologous bone grafting is felt by many to be the ideal material for cranioplasty due to low complication rates, but it is obviously available only in limited quantities and resorption may occur.

Answer 131

E The most common malignancy associated with leukoplakia is squamous cell carcinoma. About 10% of leukoplakic lesions progress to malignancy, and frequency is related to the site of occurrence. Leukoplakia of the floor of the mouth is associated with over 60% squamous cell carcinoma in situ or invasive squamous cell carcinoma, whereas leukoplakia of the buccal mucosa is almost always found to be benign. Speckled gray or white patches are more likely to develop into carcinoma. Predisposing factors include smoking, alcohol, and oral snuff. Oral leukoplakia is classified as a premalignant lesion because it is caused by exposure to the same agents that induce squamous cell carcinoma, namely smoking, alcohol, irritation from dentures or a jagged tooth, and occurrence adjacent to squamous cell carcinoma. Leukoplakia with dysplasia is not associated with other melanoma or nonmelanoma malignancies of the mouth, such as basal cell carcinoma, melanoma, Merkel cell carcinoma, or cutaneous lymphoma.