Chapter 16: Head and neck Flashcards
Most common fibroproliferative lesions of the oral cavity
- fibroma
- pyogenic granuloma
- peripheral ossifying fibroma
- peripheral giant cell granuloma (multinucleate giant cells separated by a fibroangiomatous stroma)
Features of irritation fibroma
- occurs at bite line
- nodular mass of fibrous tissue with minimal inflammation and covered by squamous epithelium
Plummer-Vinson syndrome
-triad of glossitis, iron deficiency anemia and esophageal dysphagia
Sequence of mutations in oral squamouc carcinomas
- p16 (9p) and 3p LOH, p53 (17p LOH), CyclinD1
- other genes with less well-known functions
Pathogenesis of oral SCC
- 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
Odontogenic cysts are classified into what 2 broad categories?
-inflammatory (e.g. periapical cyst) and developmental (e.g. odontogenic keratocyst)
Dentigerous cyst
- 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
Odontogenic keratocyst
- 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)
Periapical cyst
- 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)
Ameloblastoma
- arises from odontogenic epithelium and shows no ectomesenchymal differentiation
- cystic and often slow growing but locally invasive
Odontoma
- most common odontogenic tumor
- composed of epithelium but also enamel and dentin
- probably a hamartoma
- cured by excision
Olfactory neuroblastoma
- arise from neuroendocrine cells of olfactory mucosa
- NSE, synapto, etc are positive
Epidemiologic features of NPC
- 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
Squamous papillomas and papillomatosis
- 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
Risk factors for laryngeal carcinoma
- smoking (dysplastic lesions may regress after smoking cessation)
- alcohol
- asbestos
- radiation
- HPV
Branchial cleft cyst
- 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
Paraganglioma
- 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
Where do most salivary gland tumors arise and about what proportion of salivary gland neoplasms are malignant?
- 65-80% arise in parotid gland
- 15-30% are malignant; malignancy more common in tumors in the sublingual and submandibular glands
