Perianal Mucinous Adenocarcinoma and Fistula-in-Ano

Abstract

Perianal mucinous adenocarcinoma originating from a benign fistula-in-ano is rare. Diagnosis is delayed because the long history suggests benignancy. Excessive mucoid anal discharge or an abscess with mucoid content should arouse suspicion. Abundant mucin production, atypical glands and cysts, and the infiltration of tumor cells are microscopic diagnostic features. Abdominoperineal resection, with pre or postoperative radiation, is the recommended treatment. The patient reported demonstrates the need for long periods of time in reporting cures. He was thought to have had a six year clinical cure with irradiation only—recurrent disease was found later. The primary role of radiation therapy, with or without chemotherapy, requires further study.