Primary melanoma originating in the gastrointestinal tract is rare and is usually in the anorectum. We describe a solitary left colonic melanoma in a 59-year-old man and review the pertinent literature. Isolated colonic melanoma is a rare diagnosis, and the published literature seems to suggest better outcomes in this group of patients with surgical excision, unlike metastasis elsewhere in the gastrointestinal tract. It is unclear how melanomas arise in tissues with no pigmented cells, as in the colon. It is possible that regressed primaries elsewhere could have been the underlying primary lesion in such patients.
