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)