2022 Volume 75 Issue 4 Pages 176-181
An 80-year-old woman visited our hospital because of anal pain and anal prolapse. Colonoscopy examination revealed a white-toned mass extending from the anal canal to the anterior wall of the rectum. Since the pathology of the biopsy tissue suggested squamous cell carcinoma showing sarcomatoid proliferation, additional immunohistological staining was required. Abdominal perineal rectal amputation and D3 dissection were performed. The postoperative pathological diagnosis was sarcomatoid amelanotic malignant melanoma, pStage IIIb. A literature search on sarcomatoid amelanotic malignant melanoma revealed that it is an extremely rare disease, with few reports of anal canal primary. In this case, multiple liver metastases and lung metastases occurred 3 months after the operation, and ilium metastases occurred 15 months later. Currently, follow-up is underway according to BSC policy.
