An Uncommon association of Adenocarcinoma with Chronic Perianal Fistula: A Case Report and Literature Review

Perianal fistula is a common clinical condition, typically resulting from abscess formation of the anal glands or as a complication of surgical intervention. Malignant transformation of chronic fistulas in ano is rare, accounting for 3% to 11% of all anal canal malignancies. Mucinous adenocarcinoma, a subtype of adenocarcinoma, is especially rare within perianal fistula tracts. Here, we report the case of a 42-year-old male with perianal pain and a discharging fistula in ano of 3 years' duration, who underwent fistula surgery but experienced recurrence. Adenocarcinoma was diagnosed through histopathological examination of a biopsy taken from the fistulous tract. While anal fistulas are generally considered benign, chronic perianal fistulas may indicate a more serious underlying condition, such as perianal adenocarcinoma. This case highlights the importance of early referral and a multidisciplinary approach for accurate diagnosis and prompt treatment.