Head and Neck Flashcards
Facial spaces and suprahyoid neck, neck infections (complete), neck cystic lesions (complete), larynx, paranasal sinus & salivary glands, anterior Skull base, and pterygopalatine Fossa.
What is the pharynx?
What are the distinct anatomic regions of the pharynx? Describe their anatomical locations.
- The pharynx is a muscular tube extending from skull base to the thoracic inlet. It is the anatomic center of the head and neck, around which the other suprahyoid spaces wrap.
- The pharynx is divided into five distinct anatomic regions:
- Nasopharynx: Top of pharynx behind the nasal cavity.
- Oropharynx: From the level of the palate to the hyoid bone, behind the oral cavity. The posterior 1/3 of the tongue is part of the oropharynx.
- Oral cavity: The space defined by the anterior 2/3 of the tongue, bounded superiorly by the palate and inferiorly by the floor of the mouth.
- Hypopharynx: From the hyoid bone to the esophagus (posterior).
- Larynx: From the hyoid bone to the trachea (anterior).
Masticator Space
Where is it located?
What does it contain?
Where does the included CN exit the skull and what does it innervate?
If you have a lesion in the masticator space, what is important to assess?
What is the DDx of a masticator space lesion?
What is the most common masticator space path?
What are the two most common malignant mandibular lesions?
What is the most common H&N tumor of childhood?
- The masticator space is located directly anterior to the parotid and contains the muscles of mastication, the mandible, and cranial nerve V3. Cranial nerve V3 (mandibular division) exits the skull through foramen ovale and innervates the muscles of mastication. If there is a lesion in the masticator space, it is important to assess for perineural spread along V3.
- Differential diagnosis of a masticator space lesion
-
Odontogenic disease
- Dental disease is the most common masticator space pathology, which can lead to an abscess.
-
Mandibular lesion
- Osteosarcoma and metastasis are the two most common malignant mandibular lesions.
-
Rhabdomyosarcoma
- Rhabdomyosarcoma is the most common head and neck tumor of childhood.
-
Odontogenic disease
Carotid Space
What is the other name for this space?
How far inferior does the carotid space extend?
What are the contents of the carotid space? Which CN is the only one that remains within the carotid space the entire way down to its inferior extension? Are there lymph nodes in carotid space?
What is the key to generating a DDx for a carotid space mass?
- The carotid space, or post-styloid parapharyngeal space, is an incomplete fascial ring surrounding the carotid artery and jugular vein. The carotid space extends from the skull base to the aortic arch.
- The contents of the carotid space include the carotid artery, carotid body, jugular vein, and several cranial nerves. The vagus nerve (cranial nerve X) is the only cranial nerve that remains within the carotid space the entire way into the thorax. In contrast, cranial nerves IX, XI and XII pass transiently through the carotid space. Though there are lymph nodes surrounding the carotid space, there are no lymph nodes contained within it.
- The pattern of displacement of vascular structures in the carotid space is the key to generating a differential diagnosis for a carotid space mass.
What is the DDx of a carotid space mass?
Describe each one and displacement pattern!
- Paraganglioma
- A paraganglioma is a benign, highly vascular neoplasm of neural crest cells, featuring intense enhancement and a characteristic salt-and-pepper appearance on MRI due to intra-tumoral flow voids.
- Paraganglioma of the carotid body (carotid body tumor) splays the external and internal carotid arteries at the carotid bifurcation.
- Paraganglioma of the vagal nerve (glomus vagale) displaces the internal and external carotid arteries anteromedially.
- Schwannoma
- Similar to glomus vagale, schwannoma (also most commonly of the vagus nerve) also displaces the carotid arteries anteromedially. Schwannoma, however, is not nearly as vascular as paraganglioma and usually does not enhance as homogeneously.
- Neurofibroma
- Neurofibromas are almost always associated with neurofibromatosis type
- Neurofibroma and schwannoma are indistinguishable by MRI.
- MNEMONIC: PNS in the carotid space
What is the parapharyngeal space?
What are its contents?
What is it’s significance?
Describe what information you can get from the paraphayngeal space.
- The parapharyngeal space (PPS) is a triangular fat-filled space with no significant contents aside from occasional ectopic minor salivary gland tissue. The parapharyngeal space is relatively conspicuous on both MRI and CT due to its fat content__.
- The direction of displacement of the parapharyngeal space by a mass lesion in an adjacent compartment is predictable and helpful in determining from which compartment a given mass originates.
- Masticator space lesions (e.g., masticator abscess) displace the PPS posteromedially.
- Parotid lesions (e.g., pleomorphic adenoma) displace the PPS anteromedially.
- Carotid space lesions (e.g., paraganglioma) displace the PPS anteriorly.
What is the perivertebral space formed by? What are its contents?
What is the prevertebral space?
What is the paravertebral space?
- The perivertebral space is formed by the deep layer of deep cervical fascia, which wraps entirely around the prevertebral and paraspinal muscles. The prevertebral space is the anterior component of the perivertebral space. The perivertebral space is in the suprahyoid neck; the paravertebral space is the analogous region in the thoracolumbar spine.
- Contents include vertebral arteries, paraspinal muscles, spinal column, and exiting nerves.
Overview of Cervical Lymph Nodes
Cervical lymph nodes are devided into how many levels?
How are the lymph node levels defined?
In an adult, 90% of H&N cancers are ___________.
What is the role of a radiologist?
Why is the radiologist’s role so freakin important?
- The cervical lymph nodes are divided into seven levels as recommended by the AJCC (American Joint Committee on Cancer), with a consistent agreement between surgeons, oncologists, and radiologists. The lymph node levels are not defined by fascial planes, but instead are defined by anatomic landmarks and organized by patterns of lymphatic spread.
- In an adult, 90% of head and neck cancers are squamous cell carcinoma.
- The role of the radiologist is not to provide a differential, but to stage the disease.
- The degree of lymph node involvement has a substantial prognostic value. For instance, a single metastatic lymph node decreases survival from squamous cell carcinoma by 50% over an equivalent period.
Level I Lymph Nodes
Included lymph nodes? Location?
Location of IA and IB lymph nodes?
- Level I lymph nodes include submental and submandibular nodes, which are superior to the hyoid bone and inferior to the mandible and mylohyoid.
- IA nodes are submental, lying between the medial margins of the anterior bellies of the digastrics.
- IB nodes are submandibular, lateral to the medial margin of the anterior belly of the digastric and extending to the posterior margin of the submandibular gland.
Level II Lymph Nodes
What are included in this lymph node level? What is the margins?
IIA nodes landmarks?
IIB nodes landmarks?
- Level II lymph nodes are upper internal jugular nodes, extending from the skull base to the inferior margin of the hyoid bone.
- IIA nodes are anterior to the posterior margin of the internal jugular vein.
- IIB nodes are posterior to the IJV but anterior to the posterior margin of the sternocleidomastoid muscle.
Level III Lymph Nodes
What named lymph nodes are at this level?
What are the anatomical landmarks?
- Level III lymph nodes are middle jugular nodes, extending craniocaudally from the inferior aspect of the hyoid to the inferior aspect of the cricoid cartilage. The posterior edge of the sternocleidomastoid is the shared posterior margin for both level III and level IIB nodes.
Level IV Lymph Nodes
What named lymph nodes are at this level?
What are the anatomic boundaries?
- Level IV nodes are inferior jugular nodes, extending from the inferior aspect of the cricoid cartilage to the clavicle. Superiorly, the posterior border is the posterior aspect of the sternocleidomastoid muscle (similar to level III and IIB nodes). Inferiorly, the posterior border is the posterior aspect of the anterior scalene muscle.
Level V Lymph Nodes
What named lymph nodes are at this level?
What are the anatomic boundaries of VA nodes?
What are the anatomic boundaries of VB nodes?
- Level V lymph nodes are posterior cervical nodes.
- VA nodes are superior, extending from the skull base to the inferior cricoid cartilage.
- VB nodes are inferior, extending from the inferior cricoid cartilage to the clavicle.
Level VI Lymph Nodes
What named lymph nodes are at this level?
What is their anatomic location?
- Level VI nodes are pretracheal nodes, which are often simply called “pretracheal.”
- They are located anteromedially in the lower neck and bounded laterally by the carotid sheaths. Level VI extends craniocaudally from the inferior aspect of the hyoid bone to the top of the manubrium.
Level VII Lymph Nodes
What are the named lymph nodes at this level?
What are the anatomic boundaries?
- Level VII nodes are superior mediastinal nodes, which are also commonly described by their location.
- They are inferior to level VI and medial to the carotid sheaths, extending craniocaudally from the superior aspect of the manubrium to the brachiocephalic vein.
Fascial Anatomy of the Retropharyngeal Space
Where is the retropharyngeal space located? Where does it extend down to? What is directly lateral to this space?
What is the alar fascia? What does it separate? Significance?
Where is the prevertebral space?
- The retropharyngeal space is a potential space located posterior to the pharynx, separated from the pharynx by the pharyngobasilar fascia. The retropharyngeal space extends from the base of the skull to the upper mediastinum. Directly lateral to the retropharyngeal space are the carotid and parapharyngeal spaces.
- The alar fascia is directly posterior to the retropharyngeal space. The alar fascia separates the retropharyngeal space from another potential space, the danger space, which acts as a trapdoor for infection to travel all the way from the neck to the diaphragm.
- The prevertebral space (the anterior component of the perivertebral space in the suprahyoid neck) is located just anterior to the vertebral body and is bounded anteriorly by the prevertebral fascia.
Fascial Anatomy of the Floor of the Mouth
Where is the sublingual space? Boundaries?
What space is directly inferior to the sublingual space?
What separates these spaces?
- The sublingual space is a potential space located at the base of the tongue, nestled between the genioglossus and geniohyoid muscles medially and the sling of the mylohyoid muscle inferiorly and laterally.
- Directly inferior to the sublingual space is the U-shaped submandibular space. The sublingual space is separated from the submandibular space by the mylohyoid muscle anteriorly, although the sublingual space is contiguous with the submandibular space posteriorly.
Retropharyngeal Abscess
What is a clinical concern of retropharyngeal abscesses?
What is the most often cause in children? What could happen to the retropharygeal lymph nodes?
What is the most common cause in adults?
- Retropharyngeal infection may cause airway compromise.
- In children, retropharyngeal infection is most often from spread of an upper respiratory tract infection, such as pharyngitis. Enlargement of retropharyngeal lymph nodes that drain the pharynx may lead to subsequent suppuration and rupture.
- In adults, retropharyngeal infection is most often due to penetrating injuries, such as fish bone ingestion or instrumentation.
Ludwig Angina
What is it?
What is a clinical priority?
Imaging?
- Ludwig angina is cellulitis of the floor of the mouth.
- It is an infection that can involve the submental, sublingual, and submandibular spaces.
- The tongue can rapidly become posteriorly displaced, so ensuring airway patency is a clinical priority.
- On imaging, there is stranding and swelling at the floor of the mouth.
Peritonsillar Abscess
This is a complication of what process?
What is the characteristic clinical finding?
- Peritonsillar abscess is a complication of peritonsillar lymph node suppuration, causing the characteristic hot-potato voice.
Ranula
What is it?
Where do they all arise from?
What is a plunging ranula?
What may also present like a plunging ranula? How do you differentiate?
- A ranula is a mucous retention cyst that arises from the sublingual gland as a sequela of inflammation.
- All ranulas arise from the sublingual gland and hence begin in the sublingual space.
- A plunging ranula extends from the sublingual space into the submandibular space by protruding posteriorly over the free edge of the mylohyoid or by extending directly through a defect in the mylohyoid.
- A dermoid cyst may also present below the mandible, but is typically midline, rather than the eccentric location of a plunging ranula.
Lemierre Syndrome
What is it?
Who is typically affected?
Most common etiology?
Imaging?
What may be present in the lungs?
- Lemierre syndrome is venous thrombophlebitis of the tonsillar and peritonsillar veins, often with spread to the internal jugular vein.
- Immunocompetent adolescents and young adults are typically affected.
- The most common infectious agent is the anaerobe Fusobacterium necrophorum, which is part of the normal mouth flora.
- Imaging shows enlargement, thrombosis, and mural enhancement of the affected veins.
- Metastatic pulmonary abscesses may be present.
Bezold Abscess
What is it?
Imaging?
- Bezold abscess is a complication of otomastoiditis where there is necrosis of the mastoid tip and resultant spread of infection into the adjacent soft tissue.
- On imaging, there is opacification of the middle ear and mastoid air cells, often with bony erosion of the mastoid.
Thyroglossal Duct Cyst
What is it due to?
How do most present?
Where are the majority located?
What is a rare complication?
- A thyroglossal duct cyst - TDC is due to the persistence of the thyroglossal duct. The thyroglossal duct follows the midline descent of the embryonic thyroid gland from the base of the tongue (foramen cecum) to its normal position in the neck.
- Most thyroglossal duct cysts present in childhood as an enlarging neck mass that elevates with tongue protrusion.
- The majority of TDCs ~65% are infrahyoid, the rest found at the level of the hyoid or above. Most are midline, but they may occur slightly off midline, especially when infrahyoid.
- Thyroid carcinoma (papillary type) is a rare complication seen in 1% of TDCs.
Dermoid/Epidermoid of the Floor of the Mouth
What is a dermoid?
CT appearance? Most commonly located where?
Pathognomonic MRI finding of a dermoid?
Otherwise, how do you differentiate dermoid with epidermoid?
- A dermoid is a teratomatous lesion that contains at least two germ cell layers, while an epidermoid contains only ectoderm.
- On CT, both dermoid and epidermoid will appear as a fluid-attenuation lesion, most commonly in the midline of the floor of the mouth. A pathognomonic MRI finding of dermoid is the sack of marbles appearance from floating fat globules. In the absence of this finding, epidermoid and dermoid can be indistinguishable in this location on MRI.
Second Bronchial Cleft Cyst
What is it?
Where do they occur?
Classic location?
How to differentiate between this and say a submandibular abscess?
What can happen to these cysts?
Are they common in adults? What should be considered in the differential in adults?
- A branchial cleft cyst - BCC is a congenital anomaly arising from the embryologic branchial apparatus. There are four types of congenital branchial cleft cysts, with the second type being the most common type.
- A second BCC may occur at any point along the path extending from the palatine tonsil to the supraclavicular region, but most occur near the angle of the mandible.
- The classic location of a second BCC is anterior to the sternocleidomastoid muscle, posterior to the submandibular gland, and closely associated with the carotid bifurcation.
- Although second BCC has been described as being in the posterior submandibular space, an infected second BCC would not typically be confused with a submandibular abscess. Submandibular abscess is usually due to dental disease and is typically located immediately inferior to the mandible.
- The cyst may become superinfected. With superinfection, the wall may enhance and there may be inflammatory changes within the surrounding soft tissues.
- Branchial cleft cysts are uncommon in older adults. A cystic metastasis (from papillary thyroid cancer or base of tongue/tonsillar squamous cell carcinoma) should be considered instead, especially if the cyst is irregular or has a mural nodule.
Submandibular/Masticator Abscess
Causes?
Imaging?
Treatment?
- A submandibular or masticator abscess may arise from dental disease (most commonly), suppurative adenopathy, or spread of adjacent salivary gland infection.
- On imaging, an abscess appears as an irregular, thick-walled, peripherally enhancing fluid collection located inferior to the mandible. Adjacent stranding of the cervical fat is usually present.
- In addition to antibiotics, aspiration is usually a key component of treatment.
What are the cystic lesions of the floor of the mouth?
What are the cystic lesions about the mandible?
- Floor of mouth:
- Ranula
- Dermoid/Epidermoid
- Thyroglossal duct cyst
- Cystic mets
- Mandible:
- Second branchial cleft cyst
- Submandibular or masticator abscess
Cystic Metastasis of the Floor of the Mouth
What two cancers can do this?
- Papillary thyroid cancer and squamous cell carcinoma from the base of tongue or the tonsils may metastasize to the floor of the mouth region. These metastases tend to be cystic.
First Branchial Cleft Cyst
Where is it usually located?
Imaging appearance?
- A first branchial cleft cyst BCC is rare and is usually located near the parotid or the external auditory canal.
- A first BCC may appear as a simple cyst; however, imaging is variable and contents may be heterogeneous, especially if superinfected.
Lymphatic Malformations
What are they?
How are they classified?
What is the most common type? What is it associated with? Most common location?
What are the other two types?
- Lymphatic malformations are congenital abnormalities that result when the embryologic lymphatics fail to connect to developing veins. There are three types of lymphatic malformations, classified by the size of the intra-lesional cystic spaces.
- Cystic hygroma is the most common type of lymphatic malformation, the majority being present at birth and associated with chromosomal anomalies including Turner and down syndromes. A cystic hygroma features large lymphatic spaces. The most common location is in the posterior triangle of the neck.
- Cavernous lymphangioma has smaller lymphatic spaces than a cystic hygroma, while a capillary lymphangioma has the smallest cystic spaces.
Thornwaldt Cyst
What is it?
Presentation?
Location?
- A Thornwaldt cyst is a notochordal remnant that is usually asymptomatic, but may be a cause of halitosis.
- The typical location of a Thornwaldt cyst is in the midline nasopharynx.
Lingual Thyroid
What is it?
Is it functioning? What should be checked?
More common in males or females?
Complications?
- Lingual thyroid is ectopic thyroid tissue that has incompletely descended during embryologic development and remains at the floor of the mouth.
- Usually, the ectopic gland is the only functioning thyroid tissue, so the neck should be evaluated to confirm the lack of normal gland.
- Lingual thyroid is much more common in females.
- Lingual thyroid is susceptible to standard thyroid pathology, including thyroiditis and cancer.
What is the larynx?
What are the cartilaginous components of the larynx?
What are the aryepiglottic folds?
What are the false vocal folds?
What is in the supraglottic larynx?
What is in the glottis? How do you ID the true vocal folds on CT or MRI?
Where is the subglottic larynx?
- The larynx is a fibrocartilaginous tube that extends from the skull base to the esophagus.
- The cartilaginous components of the larynx include the epiglottis, thyroid cartilage, cricoid cartilage, and arytenoids.
- The cricoid cartilage is a complete ring that provides support for the larynx.
- The entire larynx, including the epiglottis, aryepiglottic folds and false vocal cords, is lined with mucosa.
- The aryepiglottic folds are an extension of the mucosa covering the epiglottis and mark the entrance to the larynx. The aryepiglottic folds connect the epiglottis anteriorly to the arytenoids posteriorly.
- The false vocal folds are mucosal infoldings superior to the laryngeal ventricle. They can be identified on cross-sectional imaging by the presence of the paraglottic fat laterally.
- The supraglottic larynx extends from the epiglottis to the ventricle. The false vocal cords, the aryepiglottic folds, and the arytenoid cartilages are within the supraglottic larynx.
- The glottis includes the true vocal cords and the thyroarytenoid muscle. The medial fibers of the thyroarytenoid muscle comprise the vocalis muscle.
- The true vocal cords are identified in the axial plane on CT or MRI by identifying the transition of paraglottic fat to muscle (thyroarytenoid muscle) within the wall of the larynx.
- The subglottic larynx begins 1 cm inferior to the apex of the laryngeal ventricles and extends to the first tracheal ring.
Laryngeal Truama
Which cartilagenous structures are susceptible to fx?
Is it easier to Dx this in young or old patients?
What else can cause laryngeal trauma?
- Blunt trauma to the neck may compress the larynx against the cervical spine. The thyroid cartilage and cricoid cartilage are susceptible to fracture, which may be difficult to detect in young patients with incomplete ossification of these structures.
- Laryngeal trauma may also result from intubation, which can cause arytenoid dislocation.
Sinus Anatomy and Mucosal Drainage
What are the sinuses lined with?
What is the ostiomeatul unit?
What single bony structure and multiple air passages make up the ostiomeatul unit?
- The sinuses are lined with ciliary mucosa that propels secretions through the drainage pathways. Each pathway should be carefully evaluated on a sinus CT.
- The ostiomeatal unit (OMU) is the common drainage pathway for the maxillary, frontal, and anterior ethmoid sinuses, which all drain into the middle meatus. Several air passages and a single bony structure (the uncinate process) make up the OMU, which is comprised of the maxillary sinus ostium, infundibulum, uncinate process, hiatus semilunaris, ethmoid bulla, and middle meatus. Some authors include the frontal recess as part of the OMU.
What are the possible bony complications of sinusitis?
What in the world is a Pott’s puffy tumor?
- Chronic inflammation of the mucoperiosteum may cause periostitis and osteomyelitis.
- Osteomyelitis of the frontal bone may cause a subgaleal abscess with associated softtissue edema, which is called Pott’s puffy tumor (ie osteothrombophlebitis from frontal sinusitis).
Chronic Allergic Fungal Sinusitis
What is this? Who does this affect?
Imaging appearance?
- Chronic allergic fungal sinusitis is a noninvasive disease caused by a hypersensitivity reaction to fungi. Most patients with allergic fungal sinusitis are immunocompetent but have a history of asthma.
- On imaging, the affected sinus is expanded and airless, with thin deossified walls. The sinus contents are typically mixed attenuation with heterogeneous curvilinear high attenuation.
What is an antrochoanal polyp?
Treatment?
Imaging appearance?
- An antrochoanal polyp is a dumb-bell shaped benign polyp extending from the maxillary sinus into the nasal cavity, with characteristic widening of involved ostium. It may erode bone and extend into the nasopharynx. Complete resection is necessary to prevent recurrence.
- Peripheral enhancement of surrounding mucosa with no central enhancement.
What is a mucocele?
Imaging appearence?
Why is it important to always look at all sequences?
- A mucocele is an expanded airless sinus that results from obstruction of the sinus ostia. mucocele may be secondary to inflammatory sinus disease (most commonly) or tumor.
- On imaging, there is thinning of the sinus walls. The contents of the sinus tend to be homogeneous on CT and MR; however, the MRI signal intensity is variable depending on the degree of desiccation of the sinus contents. Specifically, with increasing chronicity, signal increases on T1-weighted images and decreases on T2-weighted images. In late disease, there can be markedly reduced signal on T2-weighted images that may actually simulate a normal air-filled sinus, so it’s important to always look at all sequences.
What is an inverted papilloma? Benignity?
Classic imaging appearance on an enhanced study? Contrast this to mucocele.
Treatment?
- An inverted papilloma is a benign lobulated epithelial tumor of the sinus mucosa; however, it can be associated with squamous cell carcinoma 10-20% of the time.
- The classic imaging finding on an enhanced study is a cerebriform pattern of enhancement, which describes curvilinear, gyriform enhancement. In contrast to a mucocele or obstructed secretions, the entire solid tumor will enhance. The tumor tends to remodel bone.
- Treatment is surgical resection and recurrences occur in approximately 15%.
Pleomorphic Adenoma
Prevalence of this tumor relative to other salivary gland tumors?
How does it present?
What is the standard of treatment?
How do you distinguish pleomorphic adenoma with a malignant mucoepidermoid carcinoma?
What does a surgeon have to be careful with?
Imaging appearance?
- Pleomorphic adenoma is by far the most common parotid tumor, accounting for 80% of all parotid tumors. The tumor typically presents as a small firm mass in a middleaged patient. There is a slight female predominance.
- Although pleomorphic adenoma is benign, complete surgical resection is the standard treatment. Left unexcised, the tumors can continue to grow, and there is an increasing risk for malignant transformation to carcinoma ex pleomorphic adenoma. Additionally, it is not possible to distinguish between benign pleomorphic adenoma and malignant mucoepidermoid carcinoma by imaging alone.
- During surgery, the capsule of the tumor must be preserved to prevent diffuse tumor seeding.
- CT is insensitive for detecting a small parotid tumor, so MRI is preferred. The T1 and T2 characteristics of a pleomorphic adenoma are similar to water. Unlike a simple cyst, however, enhancement is typical for pleomorphic adenoma.
Sarcoid in the Parotids
How often are the parotids invloved in patients with sarcoidosis? Typical presentation?
What clinical presentation involving the parotids is considered pathognomonic for sarcoidosis?
What is the panda sign??
- Involvement of the parotid gland is seen in up to 30% of patients with sarcoidosis, typically presenting as bilateral painless swelling.
- Uveoparotid fever, which presents with bilateral uveitis, parotid enlargement, and facial nerve palsy, is considered pathognomonic for sarcoidosis.
- Gallium-67 scintigraphy produces the classic panda sign from increased uptake by the lacrimal and parotid glands.
Sjögren Syndrome
What is it?
What is secondary and primary Sjögrens?
Who does it typically affect?
Imaging appearance?
Sjögren syndrome increases the risk of what? When should you be concerned for this?
- Sjögren syndrome is an autoimmune disorder that affects the major and minor salivary glands as well as the lacrimal glands. When secondary to a systemic connective tissue disorder such as rheumatoid arthritis, the disease is referred to as secondary Sjögren syndrome. When only the salivary and lacrimal glands are affected, the disease is called primary Sjögren syndrome.
- Sjögren syndrome typically affects middle-aged females.
- On imaging, there is atrophy and fatty replacement of the salivary glandular tissue, with multiple nodules, abnormal enhancement, numerous small cystic foci, and punctate calcification.
- The risk of parotid and head and neck lymphoma is markedly increased in patients with Sjögren syndrome. Any new dominant parotid mass in the settng of Sjögren syndrome should raise concern for lymphoma.
HIV Lymphoepithelial Lesions
What is HIV’s manifestation in the salivary glands? Appearance?
Which gland is affected and why?
- Patients with HIV frequently have parotid manifestations of lymphoid dysfunction, including multiple bilateral lymphoepithelial cysts and solid masses.
- The parotid glands are the only salivary glands containing intrinsic lymphoid tissue. Therefore, only the parotid glands are affected in patients with lymphoepithelial lesions.
Anatomy of the Pterygopalatine Fossa
What is so significant of the pterygopalatine fossa?
Where is this fossa situated? How many sides does it have?
Asymmetry in the fossa should raise concern for what?
What are the contents of this fossa?
- The pterygopalatine fossa is the bridge between the face and the brain, and is an important potential pathway for the spread of tumor or infection.
- The pterygopalatine fossa sits directly posterior to the maxillary sinus and inferior to the inferior orbital fissure. It can be thought of as a three-dimensional box with each of the six sides leading to important structures in the face.
- The pterygopalatine fossa should contain symmetric fat and soft tissue. Asymmetry in the pterygopalatine fossa should raise concern for a mass, such as lymphoma orperineural spread of a salivary tumor (e.g., adenoid cystic carcinoma).
- The contents of the pterygopalatine fossa are the pterygopalatine ganglion and branches of the internal maxillary artery.
What are the foramina of the pterygopalatine fossa and central skull base?
Include anatomic locations, contents, and possible clinical significance of each!
- The pterygomaxillary fissure is the lateral exit of the pterygopalatine fossa, which leads into the masticator space.
- The sphenopalatine foramen is the medial exit of the pterygopalatine fossa. It leads into the nasopharynx via the superior meatus. The nasal margin of the sphenopalatine foramen is thought to be the site of origin of juvenile nasopharyngeal angiofibroma.
- Foramen rotundum is the posterior opening to the middle cranial fossa. Cranial nerve V2 travels through foramen rotundum.
- The inferior orbital fissure is the “roof” of the pterygopalatine fossa and opens anteriorly into the orbit. The infraorbital nerve and artery travel through the inferior orbital fissure.
- The vidian canal is located directly below foramen rotundum. It contains the vidian nerve and vidian artery, also known as the nerve and artery of the pterygoid canal.
- The pterygopalatine canal is the “floor” of the pterygopalatine fossa, which leads to the oral cavity via the greater and lesser palatine foramina. The pterygopalatine canal transmits the descending palatine nerve and artery.
Juvenile Nasopharyngeal Angiofibroma
What is this? Presentation?
Metastatic potential?
Where does this tumor arise from?
Imaging appearance? Three classic findings of JNA?
Treatment?
- Juvenile nasopharyngeal angiofibroma (JNA) is a benign, highly vascular tumor seen in adolescent males. The most common clinical presentation is nasal obstruction and epistaxis.
- Despite the lack of metastatic behavior, JNA is very locally aggressive and insinuates through adjacent skull base foramina. Tumors frequently recur if incompletely resected.
- JNA arises from within the nasal aspect of the sphenopalatine foramen, which is the medial boundary of the pterygopalatine fossa.
- On imaging, JNA enhances very avidly and is centered in the nasopharynx. As the mass continues to grow, extension into the pterygopalatine fossa or the orbits is commonly seen.
- The three classic findings of JNA include:
- Nasopharyngeal mass.
- Expansion of the pterygopalatine fossa.
- Anterior bowing or displacement of the posterior maxillary sinus wall.
- Pre-operative embolization is often performed to reduce the vascularity of the lesion prior to resection.
Enthesioneuroblastoma
What is the other name for this disorder?
What is this tumor and what is it’s histology similar to?
Epidemiology?
Imaging appearance?
Classif finding that is thought to be pathognamonic?
- Esthesioneuroblastoma, also known as an olfactory neuroblastoma, is a malignant neural crest tumor that arises from specialized olfactory epithelium. The histology is similar to other neural crest tumors, such as small cell lung carcinoma and neuroblastoma.
- Esthesioneuroblastoma affects patients in a bimodal age distribution, with peak incidence in the teenage years and middle age.
- On imaging, the tumor appears as an aggressive mass that is slightly hyperattenuating on CT and intermediate intensity on both T1- and T2-weighted images due to high cellularity. Calcification is often present.
- A classic finding, thought by some authors to be pathognomonic of esthesioneuroblastoma, is the presence of peripheral tumor cysts that occur at the margins of the intracranial portion of the mass.
