Assessing the Value of Histology and Anatomic Segment Evaluation Among Patients Undergoing Pouchoscopy

The value of histologic assessment after ileal pouch-anal anastomosis (IPAA) has not been definitively determined. We evaluated the correlation between histology and endoscopic findings, as well as the proportion of patients with inflammation in areas beyond the pouch body on their initial pouchoscopy after IPAA.

In a retrospective cohort study, we evaluated patients who underwent IPAA for UC between 2012 and 2020 and subsequently underwent a pouchoscopy with routine biopsies of the pouch body, pre-pouch ileum, and rectal cuff. We compared endoscopic and histologic assessments in each location using χ2 testing and Spearman correlation, as well as the development of pouchitis and Crohn's-like disease of the pouch (CLDP) in longitudinal follow-up.

Among 126 patients, the median time to pouchoscopy after IPAA was 384 days, with 82 patients (65%) having inflammation of the pouch body. Significantly more patients with pouch body inflammation had histologic inflammation compared with patients without pouch body inflammation (96% vs 22%, P < .001, r = 0.769). Additionally, 16 patients (13%) were found to have endoscopic inflammation of the pre-pouch ileum with corresponding histologic inflammation in 88%; of these, 31% later developed CLDP. In contrast, 13% of patients with no endoscopic inflammation displayed histologic inflammation, with none later developing CLDP. Forty-six percent of patients had rectal cuff inflammation (correlation with histologic inflammation r = 0.580).

In our evaluation, the added benefit of histology in the presence of visible endoscopic inflammation for disease activity assessment scores is unclear. The prognostic value of histologic inflammation without endoscopic inflammation warrants a longitudinal study.