Primary anorectal malignant melanoma: report of two cases.

Primary anorectal malignant melanoma is a fairly uncommon but highly malignant disease. It is sometimes mistaken for benign conditions such as hemorrhoids or rectal polyps. Here we describe two cases of primary malignant melanoma of the rectum: in one patient a wide local excision (WLE) was performed and in the other an abdominoperineal resection (APR), both with curative intent. Both patients developed systemic recurrences and died of their disease at 24 and 10 months, respectively. In conclusion, the prognosis of anorectal melanoma is poor, irrespective of surgical treatment. WLE is the first choice for primary anorectal melanoma, while APR should be reserved for those cases where complete transrectal tumor resection is technically impossible.