Anorectal melanoma--3 case reports and a review of the literature.

Anorectal melanoma is an uncommon disease. Histologically, the tumor may mimic adenocarcinomas, small cell carcinomas, and sarcomas; grossly, the lesion often mimics hemorrhoids. We report 3 cases of anorectal melanoma: a 40-year-old woman with anorectal melanoma with local recurrence after an abdominoperineal resection (APR); a 30-year-old woman with anorectal melanoma and multiple liver metastases returning with multiple masses in the rectum...