Rhinology Tumors and Skull Base Disease

Question 1

What type of papilloma arises within the nasal
vestibule and nostril from stratified squamous
epithelium, is more common in males, and can be
treated by simple excision or cauterization?

Answer 1

Vestibular (keratotic) papilloma

Question 2

What three types of papillomas arise in the nasal

cavity?

Answer 2

● Fungiform papilloma (also called exophytic, septal, or
everted papilloma)
● Inverted papilloma (also called Schneiderian, epithelial,
transitional cell, or Ringertz papilloma)
● Oncocytic papilloma (also called cylindrical)

Question 3

Where do everted papillomas of the nasal cavity

most commonly arise?

Answer 3

Nasal septum (rarely: inferior turbinate, nasal vestibule,
nostril)

Question 4

Describe the gross and microscopic
characteristics of everted papillomas of the nasal
cavity.

Answer 4

● Gross: Raised, verrucous, 1 to 15 mm in diameter, single,
unilateral, attached to mucosa via a broad base
● Micro: Branching fronds of mucosa with a connective

tissue core with stratified squamous epithelium; koilocy-
tosis is common

Question 5

What human papillomavirus (HPV) subtypes are
commonly associated with everted nasal
papillomas?

Answer 5

HPV 6 and 11.

Question 6

What is the treatment for everted papillomas of

the nasal cavity?

Answer 6

Simple excision or cauterization. Rare recurrence or trans-

formation

Question 7

Where do inverted papillomas most commonly
arise within the nasal cavity, and from what
epithelial subtype do they originate?

Answer 7

Lateral nasal wall. May also arise from ethmoid air cells or
maxillary sinus. Unilateral > > > bilateral. Schneiderian epi-
thelium.

Question 8

What patient demographic most commonly has

inverted papillomas?

Answer 8

White men (0.75F:1M) in their 60 s and 70s

Question 9

Describe the gross and microscopic characteristics

of inverted papilloma.

Answer 9

● Gross: Unilateral, pale pink to reddish gray, polypoid
(“mulberry”) mass arising from a stalk (can be broad or
narrow), irregular, friable, often firmer than inflammatory
polyps, although may be difficult to differentiate

● Microscopic: Hyperplastic ribbons of basement mem-
brane and epithelium invaginating into the underlying

stroma. Stroma demonstrates inflammatory changes
containing fibrosis and edema. Multilayered squamous,

columnar, or transitional cell epithelium (or a combina-
tion) containing mucocytes and intraepithelial mucous

cysts

Question 10

Which HPV subtypes are most commonly

associated with inverted papilloma?

Answer 10

HPV 16 and 18 although 6 and 11 have been seen as well

Question 11

What is the incidence of malignant degeneration
of inverted papillomas to squamous cell
carcinoma?

Answer 11

5 to 10%
Note: Adenocarcinoma and small cell carcinoma have also
been identified.

Question 12

Although the risk of recurrence for inverted
papilloma is high, what might increase the risk of
recurrence?

Answer 12

Surgical approach and multicentricity of the tumor

Question 13

What two imaging modalities are used most com-

monly during the workup for inverted papillomas?

Answer 13

● Contrast-enhanced CT: Demonstrates bony destruction,
including erosion, remodeling, and sclerosis; may dem-
onstrate areas of calcification within the lesion
● Contrast-enhanced MRI: Can differentiate inspissated
secretions, mucoperiosteal thickening, and inflammatory
changes. T1 lesion is ~ hyperintense to muscle; T2
inspissated secretions and inflammatory polyps are
hyperintense.

Question 14

What are the treatment options available for sino-

nasal inverted papilloma?

Answer 14

● Complete surgical excision: Endoscopic or open
● Radiation therapy
● Observation

Question 15

What are the surgical approaches used for endo-scopic and open surgical resection of inverted
papillomas?

Answer 15

● Endoscopic: En bloc wide local excision, medial max-
illectomy, Sturman-Canfield operation (Denker opera-
tion), Draf procedure

● Open: Lateral rhinotomy, midfacial degloving, osteo-
plastic flap, frontal sinus trephination

Note: The key is subperiosteal dissection, removal of all
involved mucosa, and drilling down the bone in contact or
attached to the papilloma.

Question 16

When is radiation therapy recommended for

inverted papilloma?

Answer 16

● For aggressive, multifocal disease
● For squamous cell carcinoma
● If patient cannot tolerate surgery or if the functional or
cosmetic results of surgical resection are not acceptable
Note: The risks of radiation include potential for malignant
conversion.

Question 17

How long should patients be followed up for
surveillance of inverted papilloma, and when
should CT scans be ordered?

Answer 17

Minimum of 5 years. Recurrence most often occurs
between 2 and 10 years. CT scans should be ordered if
scarring limits full visualization of the resection cavity, if the
patient is symptomatic, or there is evidence of recurrence.

Question 18

What is the least common unilateral Schneiderian

nasal papilloma?

Answer 18

Oncocytic (cylindrical) papilloma, 3 to 5% of all sinonasal

papillomas

Question 19

You are evaluating the pathology report on a
patient with a lateral nasal papilloma; biopsy was
performed at an outside hospital. The report
describes endophytic invaginations of tall columnar,
multilayered epithelium composed of oncocytes
and containing microcysts laden with mucin and
neutrophils. What is the most likely diagnosis?

Answer 19

Oncocytic (cylindrical) papilloma

Question 20

What is the reported malignant potential of
oncocytic papillomas, and what histologic findings
have been reported?

Answer 20

10 to 17% (although controversial); squamous cell carci-
noma (most common), mucoepidermoid carcinoma, small
cell carcinoma, and undifferentiated carcinoma

Question 21

Similar to inverted papillomas, oncocytic
papillomas can be locally aggressive and have a
relatively high rate of recurrence. What is the best
management strategy for these tumors?

Answer 21

Complete surgical excision, as for inverted papillomas

Question 22

What is the most common benign nasopharyngeal
tumor that most commonly affects prepubescent
males at an average age of 14 to 15 years (range:
10 to 25)?

Answer 22

Juvenile nasopharyngeal angiofibroma

Question 23

Describe the major hypotheses put forth to explain the development of juvenile
nasopharyngeal angiofibromas.

Answer 23

● Incomplete regression of the first branchial arch artery
● Development from embryologic chondrocartilage of the
skull base at the junction of the palatine bone, horizontal
ala of the vomer, and root of the pterygoid process.
● Abnormality of the pituitary androgen-estrogen axis

Question 24

What is the most common blood supply to

juvenile nasopharyngeal angiofibromas?

Answer 24

Internal maxillary artery
Note: May also arise from ascending pharyngeal, external/
internal/carotid artery, and occasionally from contralateral
supply

Question 25

What are the two most common symptoms de- scribed by patients with juvenile nasopharyngeal angiofibromas?

Answer 25

Epistaxis and unilateral nasal obstruction. More progressive symptoms can include middle ear effusion, facial deformity, headache, dacryocystitis, rhinolalia, palatal deformity, hyposmia/anosmia, cranial neuropathies, and massive hemorrhage.

Question 26

Describe the characteristic gross appearance of a | juvenile nasopharyngeal angiofibroma.

Answer 26

Well-circumscribed, smooth, lobulated, purple to reddish | hue, compressible

Question 27

Describe the characteristic routes of spread or patterns of growth associated with juvenile naso- pharyngeal angiofibromas.

Answer 27

● Pterygopalatine (sphenopalatine) fossa → ● Orbit → middle cranial fossa ● Masticator space → intracranial cavity ● Infratemporal fossa → cheek or intracranial cavity ● Nasal cavity → ● Paranasal sinus (i.e., sphenoid sinus → intracranial cavity) ● Nasopharynx Note: Dural invasion is rare.

Question 28

CT, MRI, and magnetic resonance angiography can each be used during the workup of patients with suspected juvenile nasopharyngeal angiofibromas. What characteristics are common?

Answer 28

● Epicenter located adjacent to the sphenopalatine fora- men within the posterior nasal cavity ● Hypervascularity after contrast enhancement ● Distinct pattern of growth ● No regional or distant metastases

Question 29

What specific findings can be seen on CT and MRI that help distinguish a juvenile nasopharyngeal angiofibroma?

Answer 29

● CT: Bony remodeling without frank bony destruction | ● MRI: Flow voids on both T1- and T2-weighted imaging

Question 30

Describe the Holman-Miller sign.

Answer 30

Anterior bowing of the posterior maxillary sinus associated with juvenile nasopharyngeal angiofibroma

Question 31

True or False. Because angiography can be used to identify a source vessel, perform carotid balloon occlusion studies if necessary, and perform preoperative embolization in patients with juvenile nasopharyngeal angiofibromas, it is considered a required step in the workup and intervention.

Answer 31

False. Angiography, when used 24 to 72 hours preoper- atively, can provide all of this information and result in decreased intraoperative bleeding and need for transfusions and can result in shrinkage of the tumor. However, it is not required and is considered controversial.

Question 32

What arguments have been made against the use of preoperative embolization in patients undergoing resection for a juvenile nasopharyngeal angiofibroma?

Answer 32

● It can potentially obscure the tumor boundaries, resulting in a higher rate of recurrence ● Complications associated with embolization are not benign: cerebrovascular accident, blindness, facial para- lysis, skin or soft tissue necrosis. ● Some argue that tumor hypoxia can decrease the radiosensitivity of these tumors.

Question 33

What is the most common staging system used | to classify juvenile nasopharyngeal angiofibromas?

Answer 33

There is no universal staging system, although several have been published. The most recent is the Radkowski system (1996). ● IA: Limited to nasal cavity and nasopharynx ● IB: Involvement of at least one paranasal sinus ● IIA: Minimal extension through the sphenopalatine fora- men to involve the medial portion of the pterygopalatine fossa ● IIB: Extensive involvement of the pterygopalatine fossa with a positive Holman-Miller sign and anterolateral displacement of the maxillary artery branches. Possible superior extension with orbital bone erosion ● IIC: Extension through the pterygopalatine fossa to involve the cheek, infratemporal fossa, or posterior to the pterygoids ● IIIA: Skull base erosion with minimal intracranial exten- sion ● IIIB: Skull base erosion with significant intracranial extension and possible cavernous sinus involvement

Question 34

What treatment options are available for patients | with juvenile nasopharyngeal angiofibromas?

Answer 34

● Surgical resection (gold standard; open vs. endoscopic vs. combined) ● Radiation therapy (30 to 36 Gy, 20 fractions; has been shown to have similar efficacy to surgery in some situations) ● Hormonal therapy (controversial and not commonly used) ● Chemotherapy (potentially used for recurrences, rarely used)

Question 35

What is the risk of recurrence for juvenile nasopharyngeal angiofibromas, and what increases this risk?

Answer 35

Up to 40%. Large tumors; intracranial extension; involve- ment of the sphenoid, base of the pterygoids, or clivus; failure to remove all the tumor; or primary radiation treatment. Most are diagnosed within the first year either based on symptoms or with MRI.

Question 36

Sinonasal hemangiomas can arise from bone, mucosa, or submucosa within the nasal cavity and sinonasal cavities. Both cavernous and capillary subtypes can be seen. Which is more common in adults?

Answer 36

Cavernous hemangiomas

Question 37

Where do sinonasal hemangiomas most commonly arise within the nasal cavity and/or paranasal sinuses?

Answer 37

● Cavernous hemangioma → lateral nasal wall or medial maxillary wall ● Capillary hemangioma → septum

Question 38

What are the most common symptoms | associated with sinonasal hemangiomas?

Answer 38

Epistaxis and nasal obstruction. For patients with heman- | giomas restricted to the bone, symptoms may include a firm, painless swelling associated with a pulsatile sensation.

Question 39

Describe the imaging characteristics of sinonasal | hemangiomas on CT and MRI.

Answer 39

● CT: Enhance on CT with contrast. It is often indistinct from turbinates and can be associated with bony destruction. ● MRI: Enhance with contrast, intermediate signal intensity, ± flow voids. If intraosseous, it may have a soap-bubble, sun-ray, or honeycomb appearance.

Question 40

What is the management of choice for sinonasal | hemangiomas?

Answer 40

Surgical resection. Can consider preoperative embolization, | especially for intraosseous lesions.

Question 41

What pathologic lesion can be seen in the sinonasal or oral cavity as a rapidly growing mass resulting in nasal obstruction and epistaxis and is composed of proliferating capillaries separated into lobules by loose connective stroma?

Answer 41

Lobular capillary hemangiomas (previously known as | pyogenic granulomas)

Question 42

What theories have been presented as explanations for the formation of lobular capillary hemangiomas?

Answer 42

● Local trauma (e.g., nose picking, nasal packing) ● Hormonal fluctuations (e.g., pregnancy) ● Infection (e.g., influence of viral oncogenes) ● AVM ● Local production of angiogenic growth factors

Question 43

What are the clinical examination findings associated with a sinonasal lobular capillary hemangioma?

Answer 43

● Purplish/red mass | ● Generally < 1 cm, but can be larger

Question 44

What is the treatment of choice for lobular | capillary hemangiomas?

Answer 44

Complete surgical excision, although recurrence has been | reported in up to 40%

Question 45

``` What benign neoplasm can develop from Zimmerman pericytes (contractile cells surrounding small vessels) and can be seen in the sinonasal tract, retroperitoneum, lower extremities, and pelvis? ```

Answer 45

Hemangiopericytoma

Question 46

What is the typical clinical presentation and gross | appearance of a sinonasal hemangiopericytoma?

Answer 46

Nasal obstruction and epistaxis. Gray/tan mass that is spongy, vascular, and polypoid in appearance and involving the sinonasal cavity and often one or more paranasal sinus

Question 47

True or False. Sinonasal hemangiopericytomas | can demonstrate malignant potential.

Answer 47

True. The risk is low, but regional metastases and death | from disease progression have been reported.

Question 48

What are the typical imaging characteristics | associated with sinonasal hemangiopericytomas?

Answer 48

● CT: Homogeneous, enhancing lesions; expansile, result- ing in bony remodeling ● MRI: Enhance on T2-weighted imaging, intermediate enhancement on T1-weighted imaging

Question 49

What are the management options available for | sinonasal hemangiopericytomas?

Answer 49

Complete surgical resection. Adjuvant radiation and che- motherapy may play a role, especially in patients with positive surgical margins. Recurrence rates of up to 19% have been reported.

Question 50

What is the most common benign tumor of the sinonasal tract that occurs as an expansile prolifer- ation of mature bone within the membranous bones of the skull and face?

Answer 50

Osteoma

Question 51

Which sinuses are most commonly involved with | osteomas?

Answer 51

Frontal > ethmoid > > maxillary > > > sphenoid

Question 52

What is the most likely diagnosis for a patient with multiple osteomas (often seen in the mandible), intestinal polyps, and epidermoid inclusion cysts and desmoids tumors?

Answer 52

Gardner syndrome (autosomal dominant)

Question 53

What theories have been described to explain | the development of osteomas?

Answer 53

● Embryologic theory (development from the junction of the frontal bone, which is membranous, and the ethmoid bone, which is cartilaginous) ● Inflammation/infection theory ● Traumatic theory ● Slow growing osseous hamartomas

Question 54

Describe the three subtypes of osteomas.

Answer 54

● Ivory (eburnated): Compact, dense bone, minimal fibrous tissue ● Mature (spongiosum): Spongy, mature bony, trabeculum composed of fibrous tissue ● Mixed: Components of both ivory and mature osteomas

Question 55

What is the average growth rate of an osteoma?

Answer 55

1.6 mm/year (range: 0.44 to 6.0 mm/year)

Question 56

Although most osteomas are asymptomatic, they can result in a mass effect such as sinus outflow obstruction and resultant pain, sinusitis, and mucocele formation or orbital symptoms, such as proptosis, diplopia, etc. Less commonly, osteomas can grow intracranially. In these situations, what complications can arise?

Answer 56

CSF leak, meningitis, pneumocephalus, abscess formation

Question 57

What imaging characteristics are associated with | osteomas?

Answer 57

● CT: Range from a high-density lesion to a less dense ground-glass appearing lesion based on the amount of mineralized bone ● MRI: Necessary only to evaluate adjacent soft tissue, trapped secretions, or mucoceles.

Question 58

How are osteomas best managed?

Answer 58

● Observation: For lesions that are asymptomatic and present a low risk for intracranial or orbital complications ● Surgical resection: Endoscopic vs. open vs. combined

Question 59

Name the following disorders associated with sinonasal exostoses: ● Hyperostosis of the inner table of the skull, thickened cancellous bone, and intact cortex sparing the midline and frequently seen in post- menopausal women ● Hyperostosis in postmenopausal women in the presence of obesity and hirsutism ● Hyperostosis associated with thickened dura in adolescent males

Answer 59

● Hyperostosis frontalis interna ● Morgagni syndrome (metabolic craniopathy) ● Acromegaly

Question 60

What characteristics can be used to differentiate | an ossifying fibroma from fibrous dysplasia?

Answer 60

An ossifying fibroma typically has a capsule and more mature bone and is more common in black women in their 30s and 40s.

Question 61

What are the imaging characteristics common to | ossifying fibromas?

Answer 61

● CT: Well-defined, multiloculated lesion, surrounded by a bony capsule ● MRI: Hyperintense T2-signal; T1-signal is intermediately intense centrally and hyperintense peripherally.

Question 62

What is the treatment of choice for ossifying | fibromas?

Answer 62

Radical surgical resection (44% recurrence rate)

Question 63

What bony disorder is due to the replacement of normal bone with fibro-osseous tissue (woven- ossified tissue, increased bony matrix, abnormal mineralization, marrow fibrosis) that can occur in monostotic, polyostotic, or syndromic (McCune- Albright) forms?

Answer 63

Fibrous dysplasia

Question 64

Describe the radiographic and histologic | appearance of fibrous dysplasia.

Answer 64

● Radiographic pattern: Expansile lesion with relatively homogeneous smooth ground-glass appearance ● Histologic pattern: Irregularly shaped, patternless woven trabecular bone within a vascularized fibrous stroma; the irregular shaped spicules can occur as (1) Chinese writing type, (2) pagetoid type, and 3) hypercellular type.

Question 65

When should intervention, the gold standard of which is surgical resection, for fibrous dysplasia be considered?

Answer 65

● Aesthetic concerns ● Compression of neurovasculature resulting in sympto- matic or functional sequelae ● Functional impairment, such as malocclusion ● To rule out malignancy

Question 66

Although rare (< 4%), malignant transformation of fibrous dysplasia can occur. What is the most common cancer associated with this transformation?

Answer 66

Osteosarcoma

Question 67

What is the rate of CSF production?

Answer 67

~ 500 mL/day or ~ 20 mL/hour

Question 68

What is the most common cause of anterior | cranial fossa CSF leaks?

Answer 68

Noniatrogenic trauma > > iatrogenic trauma > nontraumatic | neoplastic process, spontaneous, congenital

Question 69

What is the most common location for sinonasal | CSF leaks to occur?

Answer 69

``` Ethmoid region (cribriform > lateral lamella) > sphenoid si- nus (lateral > midline) > > frontal sinus ```

Question 70

What is the name given to the congenital dehiscence seen in some patients in the lateral sphenoid roof and is thought to be due to persistence of the lateral craniopharyngeal canal?

Answer 70

Sternberg canal

Question 71

Describe the reservoir sign.

Answer 71

A change in head position, generally leaning forward that results in a gush of fluid (CSF) collected in an anatomical depression or open sinus

Question 72

How much CSF is required to test for β-2 | transferrin, a protein that is highly specific to CSF?

Answer 72

0.4 mL

Question 73

What imaging modality can demonstrate the site of a CSF leak in the absence of an obvious bony abnormality based on fine cut CT scanning?

Answer 73

CT cisternography (requires intrathecal contrast) Note: MRI cisternography using highly weighted T2 images does not require intrathecal contrast but does not demonstrate the bony anatomy.

Question 74

In a patient with an anterior skull base defect resulting in CSF rhinorrhea after blunt head trauma, what is the best first course of action?

Answer 74

Conservative management: stool softeners, bed rest, | lumbar drain, and prophylactic antibiotics

Question 75

What are the potential side effects or complications associated with the use of low-dose intrathecal fluorescein?

Answer 75

In order of frequency (most to least): Malaise, headache, dizziness, nausea, vomiting, back pain, lower-extremity weakness, tinnitus, neck pain, fever At higher doses, seizures and cranial neuropathies have been reported.

Question 76

What two grafting techniques can be used to | repair skull base defects?

Answer 76

Overlay: Graft material is placed over the defect on the sinonasal side. Underlay: Graft material is placed over the defect on the intracranial side. The two techniques are often used in combination. Grafts may include mucosa, mucoperiosteum, bone, cartilage, synthetic material, vascularized local flaps, or free flaps.

Question 77

Which patient demographic is at highest risk for developing idiopathic intracranial hypertension, which is thought to be due to chronically elevated intracranial pressure?

Answer 77

Obese women of childbearing age. Recurrent disease is associated with the number of pregnancies. Note: This condition was reviously referred to as benign intracranial hypertension and pseudotumor cerebri.

Question 78

Describe the head and neck symptoms associated | with idiopathic intracranial hypertension.

Answer 78

Headache, transient visual obscurations, papilledema, pulsatile tinnitus; no localizing signs with the exception of abducens nerve palsy

Question 79

In patients with known idiopathic intracranial hypertension and a history of recurrent CSF leak, what additional interventions can decrease the risk of recurrence?

Answer 79

● Weight loss ● Daily acetazolamide ● Ventriculoperitoneal shunt