Chapter 16: Head and neck

Question 1

Most common fibroproliferative lesions of the oral cavity

Answer 1

• fibroma
• pyogenic granuloma
• peripheral ossifying fibroma
• peripheral giant cell granuloma (multinucleate giant cells separated by a fibroangiomatous stroma)

Question 2

Features of irritation fibroma

Answer 2

• occurs at bite line

- nodular mass of fibrous tissue with minimal inflammation and covered by squamous epithelium

Question 3

Plummer-Vinson syndrome

Answer 3

-triad of glossitis, iron deficiency anemia and esophageal dysphagia

Question 4

Sequence of mutations in oral squamouc carcinomas

Answer 4

• p16 (9p) and 3p LOH, p53 (17p LOH), CyclinD1

- other genes with less well-known functions

Question 5

Pathogenesis of oral SCC

Answer 5

• linked to alcohol and tobacco, and betel nut chewing, chronic irritation
• 50% linked to HPV infection (especially tonsillar crypts, base of tongue and oropharynx)
• better prognosis than HPV-negative tumors

Question 6

Odontogenic cysts are classified into what 2 broad categories?

Answer 6

-inflammatory (e.g. periapical cyst) and developmental (e.g. odontogenic keratocyst)

Question 7

Dentigerous cyst

Answer 7

• arises around the crown of an unerupted tooth
• radiology: unilocular
• thin lining of stratified squamous epithelium often with dense inflammation
• complete excision curative but if residual left, can transform to ameloblastoma or SCC

Question 8

Odontogenic keratocyst

Answer 8

• unilocular or multilocular
• M>F, posterior mandible
• corrugated parakeratotic or orthokeratotic squamous lining
• aggressive with high recurrence rate
• multiple are associated with Gorlin syndrome (PTCH tumor suppressor on 9q22)

Question 9

Periapical cyst

Answer 9

• inflammatory cyst at apex of tooth associated with pulpitis
• may evolve to periapical abscess or develop into granulation tissue (aka periapical granuloma, but no true granuloma)

Question 10

Ameloblastoma

Answer 10

• arises from odontogenic epithelium and shows no ectomesenchymal differentiation
• cystic and often slow growing but locally invasive

Question 11

Odontoma

Answer 11

• most common odontogenic tumor
• composed of epithelium but also enamel and dentin
• probably a hamartoma
• cured by excision

Question 12

Olfactory neuroblastoma

Answer 12

• arise from neuroendocrine cells of olfactory mucosa

- NSE, synapto, etc are positive

Question 13

Epidemiologic features of NPC

Answer 13

• children in Africa, adults in China, rare in north america
• EBV in undifferentiated and nonkeratinizing types
• often remain localized and unidentified for years and present finally as cervical node metastases
• radiosensitive, particularly undifferentiated type

Question 14

Squamous papillomas and papillomatosis

Answer 14

• juvenile laryngeal papillomatosis = multiple papillomas in children, which may regress at puberty
• usually single in adults
• HPV 6 and 11 are implicated
• recurrence but minimal malignant potential

Question 15

Risk factors for laryngeal carcinoma

Answer 15

• smoking (dysplastic lesions may regress after smoking cessation)
• alcohol
• asbestos
• radiation
• HPV

Question 16

Branchial cleft cyst

Answer 16

• lateral border of SCM muscle
• arise from remnants of the 2nd branchial arch
• lined by stratified squamous or pseudostratified columnar epithelium with lymphoid tissue and germinal centres in the wall

Question 17

Paraganglioma

Answer 17

• mutations in genes encoding succinate oxidoreductase
• 2 sites: paravertebral ganglia (often sympathetic, secrete catecholamines=chromaffin positive) and paraganglia related to vessels of the head and neck (parasympathetic; rarely secrete catecholamines)
• Zellballen surrounded by delicate vascular septae
• main cells are positive for neuroendocrine markers
• supporting sustentacular network positive for S100
• can be seen in MEN2
• histology does not predict behaviour

Question 18

Where do most salivary gland tumors arise and about what proportion of salivary gland neoplasms are malignant?

Answer 18

• 65-80% arise in parotid gland

- 15-30% are malignant; malignancy more common in tumors in the sublingual and submandibular glands