malignant tumour of keratinocytes from epidermal layer of skin

2nd most common skin cancer

Demographics: fair, over 40yo, male

Risk factors:

• cumulative prolonged UV exposure
• Previous SCC or other SkCa
• smoking (esp fro lip SCC)
• type 1 skin
• chronic wounds/inflammation (arising in scares and ulcers - Marjolins ulcer)
• immunosuppression

Aetiology

1. Sun damage: cumulative, lifetime sun exposure.
   1. Invasive SCC may develop on chronically sun damaged skin secondary to changes in actinic keratoses or Bowen’s disease or may arise de novo.
2. Viral transformation
   1. certain premalignant sub-types of HPV thought to cause some carcinomas of anogenital skin
3. Rare
   1. Old Radiation sites
   2. Chronic ulcers, badly burnt skin,
   3. Cutaneous lupus
   4. Chronic Arsenic ingestion

Features: