Small-Bowel Metastatic Melanoma From Primary Mucosal Melanoma of the Anus: A Comprehensive Case Report

Anorectal mucosal melanoma (ARMM) is exceptionally rare, highly malignant, and characterized by a poor prognosis. We present the case of a 76-year-old woman with ARMM and recurrent gastrointestinal (GI) bleeding/anemia caused by small-bowel metastases, which was successfully managed with laparoscopic resection. ARMM is an aggressive type of cancer that has the potential to metastasize to the GI tract approximately 4.5 years after the primary diagnosis. Intussusception and GI bleed are potential complications. Small-bowel metastatic melanoma typically goes undiagnosed until autopsy and requires a multidisciplinary approach. Key treatment options include surgery and immunotherapy to improve patient outcomes.