Module 3 - Skin & Soft Tissue Lesions
Squamous Cell Carcinoma
Clinical Information:
- Second most common cancer among whites
- Most common cancer of darkly pigmented people
- Unlike BCC, substantial risk of metastasis
- Major cause is sun exposure (UVB)
- Can develop on any sun-exposed area, including mucous membranes, but most often on scalp, back of hand, and the superior surface of the pinna. BCC is rarely found on these sites.
Risk Factors:
- Childhood sun-exposure/burns
- Light skin and eye colour, red/blonde hair
- Freckling, facial telangiectasia
- Actinic keratosis
- Skin diseases (Bowen’s)
- Chemical exposure (arsenic, tar)
- Sites of chronic infection (chronic sinus tracts, osteomyelitis)
- Thermal burn scars (Marjolin’s ulcer), radiation
- Immunosuppression (transplant patients)
Morphology:
- If SCC arises form actinic keratosis, it tends to be a soft and movable mass with a scaly surface and a red, inflamed base. These SCC are slow growing, locally invasive, non-metastatic lesions
- If not preceded by actinic keratosis, tends to be a firm, elevated and movable mass with a sharply defined border and little surface scale. This form of SCC is often more aggressive with rapid growth, invasion, and metastatic spread
Treatment:
- Excisional biopsy (5 mm margin for tumours <1 cm; 1-2 cm margin if >2 cm)
- Moh’s micrographic surgery (only in specialized centres)
- Curettage with electrodesiccation (superficial squamous carcinomas)
- Cryotherapy
- Radiation therapy (only in special circumstances)
Author: SP Zinn