Risk of dysplasia in long-term ileal pouches and pouches with chronic pouchitis

Background & Aims: Recent reports have suggested the mucosa of an ileal reservoir could be at risk of neoplasia. Risk factors may include the age of the pouch, chronic pouchitis, and previous colonic neoplasia. This study examined a group of such patients to determine the risk of dysplasia. Methods: From a cohort of 1221 patients with ileal pouches, 171 patients with possible risk factors were selected. Successful contact was made with 138 patients who were invited for endoscopy and multiple biopsies. Biopsy specimens were stained with H&E and p53, scored for inflammatory changes including villous atrophy, and analyzed by flow cytometry. Results: One hundred six patients took part and fell into 1 or more of the following clinical categories: chronic pouchitis (n = 34), pelvic pouch for greater than or equal to 12 years (n = 42); Kock pouch for greater than or equal to 14 years (n = 29), and neoplasia in colectomy specimen (n = 11). Thirty-three patients had severe villous atrophy. One patient of 106 (95% confidence interval, 0.9%+/-1.6%) with a long-standing pouch had low-grade dysplasia that was multifocal. DNA analysis by flow cytometry showed aneuploidy in this patient and 2 others. Conclusions: These data suggest that the development of dysplasia in ileal pouches performed for ulcerative colitis is probably is a rare event within 15-20 years of pouch surgery.