Adenocarcinoma arising from chronic perianal crohn's disease: a case report.

Malignant transformation of perineal fistula in Crohn's disease has rarely been reported. We report a case of Crohn's disease with recurrent perineal fistulas. A 36-year-old male, diagnosed with Crohn's disease at the age of 24, developed adenocarcinoma in an anorectal fistula that had existed for years.