Incidence
- Melanoma makes up <1% of anal malignant tumours
- Not associated with sun exposure Clinical
- The lesion may mimic a thrombosed external haemorrhoid because of its colour, although amelanotic tumours also occur.
Prognosis
- Poor prognosis (10-20% 5-year survival)
- Median 18month survival
- Liver and lung metastases common.
Treatment
- Little benefit of radical surgery, chemotherapy and radiotherapy.
- APR had no survival benefit over local excision but may be better local control.
- Given chances of cure low, local excision may be better option for palliation.
- Immunotherapy may be an option (poor response) - see Melanoma