Adenocarcinoma of the ileoanal pouch anastomosis: an emerging complication?

Background and aims: Restorative proctocolectomy with ileoanal pouch anastomosis (IPAA) is currently the surgical treatment of choice for ulcerative colitis. Although dysplastic changes to the native ileal mucosa of the pouch occur in a subgroup of patients with severe chronic pouchitis, the development of cancer in the pouch itself is a very rare event. To date, only two cases of carcinoma of the IPAA have been reported, namely in patients operated on for colon cancer complicating ulcerative colitis and with a previous diagnosis of backwash ileitis. Case report: We report a patient with carcinoma in an ileoanal pouch who had been suffering from chronic atrophic pouchitis early after surgery. He had no previous history of colon cancer or backwash ileitis. The adenocarcinoma was detected 22 months after IPAA, and it was deeply infiltrating the adjacent structures (pT4N0M0, grade 2). Histology revealed the passage from chronic atrophic pouchitis to dysplastic epithelium and to cancer. Conclusion: Our case suggests that malignant transformation of the IPAA may occur as a pure complication of the severe chronic pouchitis, even in the absence of backwash ileitis or a previous history of colon cancer.