Anorectal malignant melanoma in Sweden. Report of 49 patients. Clinicopathologic features and prognosis of 49 patients with anal malignant melanoma were investigated in the total Swedish population between 1970 and 1984. Median age was 71 years (range, 50 to 87 years), and there was a female predominance (31 females, 18 males). The most common symptom at presentation was bleeding. The majority of tumors ranged between 2 and 5 cm in diameter and all invaded at least into the submucosa and/or the lamina propria. At diagnosis, one third of the patients had either regional or distant metastasis with a median survival of 5 months. The remaining patients were surgically treated with curative intent, either by abdominoperineal resection (APR) or local excision. Median survival was poor in both treatment groups (APR, 12 months; local excision, 13 months). Most patients died with distant metastasis. Our results confirm the opinion that APR offers no more curative potential than a more conservative surgical approach. However, tumor sizes were on average smaller in the group treated by local excision. This could indicate that, in the absence of known distant metastasis, radical surgery should be performed, particularly since local recurrences tended to be more common after a local excision. 