Annals of Coloproctology  2016;32(5):190-194

doi:10.3393/ac.2016.32.5.190

Synchronous Primary Anorectal Melanoma and Sigmoid Adenocarcinoma.

Inju CHO 1 ; Kyung Jong KIM ; Sung Chul LIM

Affiliations

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Keywords

Melanoma; Adenocarcinoma; Anus; Rectum; Sigmoid colon

Country

Republic of Korea

Language

English

Abstract

A primary anorectal malignant melanoma is a rare tumor. Moreover, cases involving a synchronous anorectal melanoma and colon adenocarcinoma are extremely rare. The authors report a case of a synchronous anorectal melanoma and sigmoid adenocarcinoma in an 84-year-old man. The regions of the anorectal melanoma showed melanocytic nevi in the adjacent mucosa of the anal canal and rectum. A dysplastic nevus was also identified in the anal mucosa. This case demonstrates that an anorectal melanoma can arise from pre-existing anorectal melanocytic lesions.