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Hairy leukoplakia • Distinctive oral lesion • Seen in immunocompromised patients • 80% of patients with hairy leukoplakia have HIV infection Hairy leukoplakia • Takes the form of – White or black – Confluent – Patches of Fluffy (hairy) – Hyperkeratotic thickenings – Almost always on the lateral border of the tongue Hairy Leukoplakia Squamous Cell Carcinoma • Oral Cavity Squamous Cell Carcinoma • 95% of cancers of Head and Neck are Squamous Cell Carcinomas arising most commonly in the oral cavity • Head and Neck Squamous Cell Carcinoma HNSCC • HNSCC is the 6th most common cancer in the world today • Long term survival is 50% Squamous Cell Carcinoma • Long term survival is only 50% because – Oral cancer is diagnosed in advanced state – Frequent development of multiple primary tumours Squamous Cell Carcinoma – Pathogenesis • Multifactorial • North America and Europe – Middle aged men – Chronic abusers of smoked tobacco – Family history – HPV infection – Actinic radiation - Sunlight (lower lip) Squamous Cell Carcinoma – Pathogenesis • Multifactorial • Outside of North America and Europe - – Chewing of betel quid - Paan in India – Betel quid contains » Areca nut, Slaked lime, Tobacco wrapped in betel leaf Squamous Cell Carcinoma • Molecular biology – Development of squamous cell carcinoma a multistep process involving a sequential activation of oncogenes and inactivation of tumour suppressor genes in a clonal population of cells. Squamous Cell Carcinoma • Molecular biology – Loss of chromosomal regions 3p and 9p21 inactivation of p16 which is a suppressor of cyclin dependent kinase – Loss of chromosome 17p with mutation of p53 tumour suppressor gene – Deletions of 4q, 6p, 8p 11q, 13q, and 14q Squamous Cell Carcinoma • Morphology – May arise anywhere in the oral cavity • Ventral surface of tongue, floor of mouth, lower lip, soft palate and gingiva – Preceded by premalignant lesions Squamous Cell Carcinoma • Morphology – Early stages • Raised firm, pearly plaques • Irregular roughened or verrucous thickening – Later • Ulcerated, protruding masses • Irregular, firm, and indurated (rolled) borders Squamous Cell Carcinoma • Morphology - Histology – Begin as dysplastic lesions – May or may not progress to full thickness dysplasia prior to invasion – Patterns range from • Well differentiated keratinizing • Anaplastic, • Sarcomatoid – Degree of keratinization does not correlate with behaviour Squamous Cell Carcinoma • Morphology - Histology – Tend to infiltrate locally before metastasizing – Routes of extension depends on primary site – Favored sites of metastasis • Cervical lymph nodes (local metastasis) • Mediastinal lymph nodes (distant metastasis), lungs, liver and bones. (often occult)
