Melanocytic Nevus on the Rectal Mucosa Removed Using Endoscopic Submucosal Dissection.

Melanocytic nevus is the benign proliferation of melanocytes. The most common location of melanocytic nevus is the skin of the extremities; however, there are few case reports of melanocytic nevus at the rectal mucosa. No prior case of malignant melanoma from melanocytic nevus at the rectal mucosa has been reported; therefore, it is unclear whether resection should be performed or close observation is sufficient. However, the potential malignant transformation of melanocytic nevus should be considered, including melanocytic nevus on the rectum. Melanocytic nevus of the skin can be removed by surgical excision; however, due to rare incidence on the mucosa of the gastrointestinal tract, the optimal treatment for rectal melanocytic nevus remains controversial. Here, we report the first case of melanocytic nevus on the rectal mucosa that was removed by endoscopic submucosal dissection. This case report provides useful information about the optimal management of rectal melanocytic nevus.