Synchronous anorectal malignant melanoma and rectal adenocarcinoma: report of a case

Synchronous neoplasms of the rectum are an uncommon condition. The situation becomes more rare when tumors are of different origin. To the authors' knowledge, synchronous anorectal melanoma and adenocarcinoma of the rectum have not been reported in the literature before.

A 67-year-old female patient with synchronous anorectal malignant melanoma and adenocarcinoma of the rectum is described. She had preoperative colonoscopic diagnosis. The different neoplasms' origin was histologically proven. Surgical management consisted of abdominoperineal resection of the rectum. Postoperatively, the patient received adjuvant chemotherapy of six cycles duration. At present, the patient has completed 32 months of follow-up. There is no evidence of recurrent disease or distant metastases.

Review of the literature confirms the rarity of anorectal malignant melanoma. On the other hand, the rectum represents the most common site for development of colonic adenocarcinoma. We were unable to trace synchronous presentation of these two tumors. Prognosis should be defined by the most malignant neoplasm; therefore, management should be focused on treating the melanoma.