Anorectal Malignant Melanoma

A 65-year-old female was admitted to Yamanashi Prefectural Central Hospital with the chief complaints of anal pain and anal bleeding. Digital examination of the rectum revealed a elastic hard tumor on the posterior wall just above the dentate line. A combined abdominoperineal resection of the rectum was carried out. Histological findings showed malignant melanoma of the anorectal junction. She died of local recurrence 14 months after the surgery. This is the 60 th case in Japan in the extent of our knowledge.Review of 60 cases in Japan is as following : Most anorectal malignant melanomas were situated at or near dentate line (histologically anorectal junction) and the posterior wall was chiefly affected (41.7 %). In 60.4 %, the estimated diameter of the lesion was 2 to 5 cm. Fourty two percent of the patients were between the ages of 60 and 69 years. The youngest patient was 25 and the eldest was 80 years. Eighteen patients were men and 42 were women a ratio of 3 :7. Of many symptoms, bleeding, constipation and pain were most frequently present. Five-year survival rate was 10.7 % and the average life expectancy after the diagnosis was 17.5 months.