Skin cancer—malignant melanoma

Malignant melanoma is a malignant tumour of melanocytes, usually arising in the epidermis. It is the most lethal of the main skin tumours and has increased almost sevenfold in incidence since the 1970s, but overall there is 90% survival at 5 years. The important pathogenic role of excessive ultraviolet (UV) radiation exposure is estimated to contribute to 86% of cases and has been the subject of public education campaigns. Genetics may be important, and up to 5% of patients have a family history of malignant melanoma.

Superficial spreading malignant melanoma

This type accounts for 50% of all British cases, shows a female preponderance and is commonest on the lower leg. The tumour is macular and shows variable pigmentation, often with regression ( Fig. 58.1 ).

Lentigo malignant melanoma

Malignant melanoma developing in a longstanding lentigo maligna ( Fig. 58.2 ) constitutes 15% of UK cases. A lentigo maligna arises in sun-damaged skin, often on the face of an elderly person who has spent many years in an outdoor occupation.