Endoscopic mucosal resection of primary anorectal malignant melanoma: a case report.

Anorectal melanoma is a rare malignant tumor with a poor prognosis. However, several studies have reported cases of long-term survival. In this report, we present a patient with anorectal melanoma who has survived for 9 years after endoscopic mucosal resection. An 85-year-old man was referred to our hospital for further examination and treatment of an anal tumor 2 cm in size. Endoscopic ultrasonography revealed that the depth of tumor invasion was confined to the submucosal layer. Endoscopic mucosal resection was performed, and the tumor was diagnosed as a malignant melanoma. The patient was followed without any additional treatment, which was per his wishes. Although melanoma recurred 4 times thereafter, endoscopic mucosal resection was performed for each recurrent lesion. Thus, he has been alive for 9 years since the first endoscopic mucosal resection without distant metastases. If the depth of tumor invasion is shallow, endoscopic mucosal resection is a useful option among other therapeutic modalities.