A Misdiagnosed Case of Anal Canal Malignant Melanoma: A Case Report.

Anal canal malignant melanoma is an uncommon malignancy. It is a highly aggressive tumor that tends to spread early in the course and present with distant metastasis. Due to the rarity of the condition, treatment is yet to be standardized. We report a case of a 47-y ear-old male patient who presented with the history of mass coming out of anus for 6 months, which was misdiagnosed as a case of hemorrhoids. Abdominoperineal resection was done based on tissue biopsy which suggested it to be a primary anal canal malignant melanoma. The diagnosis was later confirmed by histopathological and immunohistochemistry studies, which was strongly positive for HMB 45 AND Melan-A.