Purpose: Inflammation, villous atrophy, colonic metaplasia, and dysplasia have been observed within the mucosa of ileal pelvic pouches after restorative proctocolectomy. This study was designed to determine the prevalence of mucosal dysplasia in ileal pouch and any associated risk factors.
Methods: Prospectively registered patients having restorative proctocolectomy were recruited. A cross-sectional study was performed using a questionnaire focusing on disease history, functional results, and pouchitis after surgery. Participants underwent screening endoscopic pouch examination using sigmoidoscopy. Mucosal biopsies were taken from six specific locations in the pouch from proximal ileal-pouch (inflow) to ileoanal anastomosis. All biopsies were performed under strict surveillance protocol regardless of patients' symptoms. Biopsies were interpreted by two pathologists unaware of each other's report.
Results: A total of 138 patients completed the protocol. Colectomy specimens from restorative proctocolectomy showed chronic ulcerative colitis in 118 (85.6 percent), familial adenomatous polyposis in 10 (7.2 percent), Crohn's colitis in 2 (1.4 percent), and indeterminate colitis in 8 (5.8 percent) patients. Twenty-two patients (18.3 percent) had dysplasia and eight (6.7 percent) had invasive cancer found in colectomy specimens after restorative proctocolectomy. Median interval between proctocolectomy and pouch biopsy was 5.4 years. Inflammatory changes were present in a majority of specimens, but these did not correlate with clinical history of pouchitis. No villous atrophy was identified. Pouch biopsies from only one patient were indefinite for dysplasia. Subsequent biopsies were negative.
Conclusions: Clinical and microscopic evidence of ileal-pouch inflammation is common. Ileal-pouch mucosal dysplasia is uncommon, occurring in only 1 of 138 patients. Villous atrophy and colonic metaplasia were not observed in this series. Routine pouch surveillance with biopsies may not be warranted.