Primary anorectal malignant melanoma: a case report.

We report a case of a 48-year-old woman with 9 months of rectal swelling and bleeding. Physical examination revealed a mass about 5 × 6 cm on the anterior wall of the rectum, 3 cm from the anal verge, and the patient underwent abdominoperineal resection (APR). After hematoxylin-eosin staining and immunohistochemical staining, it was considered an ARM, which is an aggressive disease with a poor survival. Immunohistochemical staining showed the tumor to be positive for S-100, Melan A, Ki67 proliferative index of 70%, and negative for HMB45. The melanoma had infiltrated the adventitia and metastasized to the (intestinal) 16/16 lymph nodes with cancerous nodule formation. There were multiple organs with metastasis (liver, spleen, pancreas, lung and subcutaneous soft tissue) three months after operation. Overall, pre-operative biopsy may be insufficient to make a definite diagnosis, and immunohistochemistry is necessary. Therefore, the gold standard treatment for ARM is oncological radical surgical resection. PMID: 32211109 [PubMed]
Source: International Journal of Clinical and Experimental Pathology - Category: Pathology Authors: Tags: Int J Clin Exp Pathol Source Type: research