[661] Beta-Catenin Immunolabeling in Serrated Epithelial Change in the Setting of Inflammatory Bowel Disease

K Jockovic, EA Montgomery, CA Iacobuzio-Donahue. Johns Hopkins University, Baltimore, MD

Background: The significance of serrated epithelial change (SEC) in the setting of inflammatory bowel disease (IBD) is not well understood. However, some interpret this finding as a preneoplastic lesion indicating further characterizations are needed. SEC is difficult to distinguish on morphologic grounds from the serrated appearance of sessile serrated adenomas, traditional serrated adenomas and hyperplastic polyps. Recently, aberrant beta-catenin nuclear labeling has been described in both sessile serrated adenomas and traditional serrated adenomas, but not hyperplastic polyps, indicating it may have value in classifying serrated epithelial lesions with neoplastic potential in the setting of IBD.
Design: Immunohistochemical labeling for beta-catenin was performed on a tissue microarray (TMA) containing 34 samples of SEC from colonic biopsies or resection specimens from 28 patients with IBD. Beta-catenin labeling was characterized with respect to membranous (normal) vs. nuclear (abnormal) location. Membranous labeling was considered normal. Nuclear labeling, accompanied by a loss of membranous labeling, was considered abnormal when observed outside the crypt bases (bottom third of crypts).
Results: The mean age of all patients was 49.0±15.5, 15 patients (54%) were male and 31 patients (93%) were Caucasian. The patients were evenly distributed between Crohn's disease (14/28, 50%) and ulcerative colitis (12/28, 43%). Two patients were classified as having indeterminate colitis. In this set of patients, 71% (24/34) of SEC lesions occurred in isolation, 9% (3/34) were noted adjacent to columnar epithelial changes indefinite for dysplasia, 6% (2/34) adjacent to low grade dysplasia, and 15% (5/34) were adjacent to with high grade dysplasia or carcinoma. Twenty-three of 34 (68%) examples of SEC were present in the left colon, 7/34 (21%) in the right colon, and three were not designated. Abnormal beta-catenin labeling was seen in 6% (2/34) of cases with SEC, both of which were located adjacent to either high-grade dysplasia or invasive adenocarcinoma. Moreover, when stratified by colonic location, 2/7 (28%) samples of SEC from the right colon had abnormal nuclear accumulation of beta-catenin, compared to 0/24 samples from the left colon (p=0.04).
Conclusions: The frequency of abnormal beta-catenin labeling in SEC parallels that recently reported for sessile serrated polyps. In some patients with IBD, the finding of SEC in the right colon may indicate the development of a sessile serrated adenoma.
Category: Gastrointestinal

Wednesday, March 24, 2010 9:30 AM

Poster Session V # 61, Wednesday Morning

 

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