Mucinous Rectal Adenocarcinoma in Perianal Crohn’s Disease Fistulas

A 47-year-old male with longstanding Crohn’s disease complicated by perianal fistulous disease is described. In this patient, presentation with a large acute ischiorectal abscess resulted in diagnosis of a complicating mucinous adenocarcinoma. Despite the relatively high frequency of perianal complications in Crohn’s disease, diagnosis of carcinoma in this setting is difficult, and survival remains poor.