Mucinous adenocarcinoma arising from recurrent perianal fistula in patient with Crohn's disease: case report

Introduction: Anal carcinoma is a rare variant of epithelial tumors of the anal canal. When associated with chronic and active anal fistulas, usually this is an aggressive cancer that has difficult diagnosis and poor prognosis. Anal fistulas are a common manifestation of Crohn's disease (CD). This study aims to report a case of mucinous adenocarcinoma originating from recurrent perianal fistula in patients with CD. Case report: A man of 43 years, with melanoderma, complaining of perianal tumors, anal pain and mucopurulent secretion, the patient was diagnosed with fistulae. Colonoscopy revealed a chronic inflammatory process associated with villous polypoid lesion in the colonic and rectal mucosa. In a new episode, where it was diagnosed, chronic colitis of rectum and sigmoid was being prescribed sulfasalazine with improvement. There were relapses and the patient underwent repeated fistulectomias. After investigation, CD was diagnosed. Computed tomography (CT) of abdomen and pelvis showed multiple perineal and gluteal collections, and the patient underwent abdominoperineal resection of the rectum. Anatomopathological exam showed invasive mucinous adenocarcinoma. A new CT showed residual growth of the lesion. The patient was referred to the oncology referral service, where chemotherapy and radiotherapy were planned. The patient developed unfavorably, and his death occurred two months after treatment.