Abstract
A 63-year-old woman complained of melena and visited a nearby clinic. She was diagnosed with anorectal malignant melanoma and was referred to our hospital. Colonoscopy revealed a half-circumferential 80-mm polypoid tumor at the anal canal to the lower rectum. Computed tomography showed a well-enhanced tumor of the rectum and a 26-mm tumor in the greater curvature of the stomach. Upper endoscopic examination revealed a black tumor, which was diagnosed based on biopsy findings as malignant melanoma. We pathologically diagnosed the patient with anorectal malignant melanoma with synchronous gastric metastasis. As anorectal malignant melanoma and metastases of stomach were both resectable according to the guideline for cutaneous malignant melanoma, we performed laparoscopic surgery. Operative findings revealed a black-colored tumor on the anterior wall of the rectum from peritoneal reflection, but there was no invasion to the vagina ; we performed abdominoperineal resection and partial resection of stomach. Here, we report a rare case of resected anorectal malignant melanoma complicated by synchronous gastric metastasis with a literature review.
