2024 年 3 巻 2 号 p. 140-145
Introduction: Anorectal malignant melanoma is a rare disease, accounting for approximately 0.4-1.6% of all malignant melanomas. The prognosis is poor due to aggressive metastasis. Case presentation: We report a case of 73-year-old woman who presented with rectal bleeding in whom colonoscopy revealed an anorectal polyp in black-toned color. The pathological diagnosis of biopsy specimens was malignant melanoma and other examinations showed no evidence of lymph node or distant metastases. Robot-assisted abdominoperineal resection combined with lymph node dissections including lymph nodes along the inferior mesenteric artery, superior rectal artery, and bilateral inguens was performed. The patient was discharged on the postoperative day 21 without any adverse events. Pathological diagnosis revealed malignant melanoma cells invaded a submucosa, with no evidence of lymph nodes metastases. As of 25 months after tumor resection, no recurrence of anorectal malignant melanoma has been identified. Discussion: The present case showed that robot-assisted surgery would be a feasible and safe surgical approach in the treatment of anorectal malignant melanoma.
