ABSTRACT

Malignant melanoma of the anorectum is a very rare tumor and lethal malignant condition. It represents 0.2%–3%1 of all malignant melanomas and 0.1%–4.6% of all anorectal tumours. The prognosis is poor, with 5-year survival of less than 5% in the most series. We aimed to inform on the experience with anorectal melanoma at our hospital in order to determine its demographic and pathologic findings, prognosis, most appropriate therapeutic options, and survival.

We reviewed retrospectively the clinical records of 6 patients with a diagnosis of anorectal melanoma and treated in our hospital between 1998 and 2011.

Five of the six patients were female. The mean age of the patients was 65,3 years (50-81). All patients were admitted to our clinic with rectal bleeding and mass. Abdominoperineal resection was performed in five patients. One patient refused an operation. She treated with chemotherapy and radiotherapy. Four of the patients died due to metastatic disease in the first year with one patient still alive at 4 months. One patient died by suicide.

In conclusion primary anorectal malignant melanoma has very poor prognosis with very aggressive clinical course, considering it as a systemic disease at the time of diagnosis. In patients who have operated with curative intent for anorectal melanoma,; treatment did not alter survival and most recurrences occur systemically regardless of the initial surgical procedure. The main prognostic factors were: size of the tumor, depth of invasion, and metastases.