Anal and peri-anal melanoma

Primary anorectal malignant melanoma is a rare entity comprising approximately 1% of all malignant tumors in the region. It is the third most common site of primary melanoma after the skin and retina. For every one case of anal melanoma, there are 8 squamous cell carcinomas of the perianal skin and anal canal and 250 adenocarcinomas of the rectum. The prognosis for anorectal melanoma is dismal with few 5-year survivors. The poor prognosis is due to the advanced stage of the disease at the time of diagnosis.