Adenocarcinoma arising from a chronic perianal fistula in a Crohn's disease patient: case report and review of the literature.

Crohn's disease patients frequently develop perianal fistulas during their life. They are also at higher risk to develop cancers. Rarely, those cancers appear within a prior chronic fistula. The main types are adenocarcinoma mostly mucinous and squamous cell carcinoma. They are generally discovered at an advanced stage with a poor prognosis because symptoms are generally the same as those of the fistula itself. Regular follow-up of chronic fistulas is then important for an early diagnosis as well as histological analysis of the fistula during surgery. There is no consensus on the ideal treatment but abdominoperineal resection is the corner stone with or without neo or adjuvant chemo-radiotherapy. This paper presents a rare case of mucinous adenocarcinoma in a chronic perianal fistula in a Crohn's disease female and provides a review of the literature.