A 41-year-old man presented with a 6-month history of changed defecation patterns and rectal bleeding. A 3-cm polypoid tumor of the lower rectum was found at rectosigmoidoscopy. Dissemination studies did not show any metastases. He underwent an abdominoperineal resection. The histopathology of the specimen showed a melanoma. Two years after the resection, metastases in the abdomen and right lung were found. He died a year and a half later.