[662] Epithelial Changes Indefinite for Dysplasia in the Pouch and Peri-Pouch but Not Rectal Cuff Is Associated with Inflammation and Warrants Close Follow-Up.

Xiuli Liu, Bo Shen, Deepa Patil. Cleveland Clinic

Background: In idiopathic inflammatory bowel disease (IBD) patients with pouch, surveillance biopsies are regularly obtained from neoterminal ileum (TI), pouch, and rectal cuff and dysplasia classified according to the established criteria for IBD into negative (NEG), epithelial changes indefinite for dysplasia (IND), low-grade dysplasia (LGD), and high-grade dysplasia (HGD). However, as this region consists of three biologically different structures [small bowel, colonized small bowel (pouch), and rectal mucosa], the assessment of dysplasia poses unique challenges. This study was undertaken to compare histologic features in IND pouch surveillance biopsies with NEG biopsies and to determine the interobserver variability in diagnosing IND and its-associated histologic features.
Design: Pouch surveillance biopsies from 18 patients with IND from 2006 to 2010 were reviewed in a blinded fashion by two GI pathologists. Features assessed included neutrophils (0-3), ulceration (0-3), villous blunting (0-3, in TI and pouch), crypt distortion (0-3), mononuclear inflammation (0-3), and eosinophils (0-3). These features were compared between IND and NEG TI/pouch biopsies as well as IND and NEG rectal cuff biopsies.
Results: 25 biopsies originally classified as IND and 47 NEG biopsies were reviewed. One case (4%) was reclassified as LGD, 6 cases (24%) as NEG, one NEG (2.1%) as IND, and one IND could not be agreed upon by the reviewing pathologists. Compared to NEG TI and pouch biopsies (N=38), IND in the TI and pouch (N=9) was associated with neutrophilic inflammation, crypt distortion, mononuclear inflammation, and eosinophilic infiltrate (p=0.01, 0.04, 0.01, 0.04, respectively), and showed a borderline association with ulceration and villous blunting (p=0.06 and 0.05, respectively). In contrast, IND in the rectal cuff (N=7) was not associated with any of these features, when compared to NEG rectal cuff biopsies (N=8). The kappa interobserver agreement was excellent for dysplasia (0.83) and moderate to good for neutrophlic infiltrate (0.67) and crypt distortion (0.43). Follow-up biopsies showed that 1/16 cases with IND progressed to HGD.
Conclusions: IND in the pouch and peri-pouch region presents as a diagnostic challenge, but can be reliably interpreted in majority of the cases. Inflammation and crypt distortion are significantly associated with IND in the TI and pouch biopsies. A larger, long-term follow-up study is required to confirm our current findings.
Category: Gastrointestinal

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 62, Tuesday Afternoon


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