[633] Histological Outcome after Treatment in Collagenous Colitis: A Long Term Follow-Up Study of 50 Patients.

Catherine E Hagen, Robert M Najarian, Helen Wang, Jonathan S Levine, Corey A Siegel, Campbell Levy, Robert Burakoff, Robert D Odze, Amitabh Srivastava. Dartmouth Hitchcock Medical Center, Lebanon; Beth Israel Deaconess Medical Center, Boston; Brigham and Women's Hospital, Boston

Background: The diagnostic features of collagenous colitis (CC) are well established. However, the long term histologic outcome of CC, and its relationship to clinical response after therapy, remains unknown. The aim of this study was to evaluate histological changes in pre- and post-treatment biopsies in a cohort of CC patients with long term follow up to determine features that may correlate with histologic and/or clinical response.
Design: 404 baseline & 454 post-treatment colon biopsies from 50 patients with CC (M/F;6/44; mean age; 55 yr), all of whom had at least one post-treatment colonoscopy with biopsies obtained ≥2 yrs after initial diagnosis (mean follow up =96 mths; range 25-216 mths), were evaluated in a blinded manner for mean and max. subepithelial collagen thickness, mean and max. intraepithelial lymphocytes (IEL), degree and extent of lamina propria (LP) inflammation and eosinophilic infiltration. Mean number of biopsies obtained at pre- (8.1) and post-treatment (9.1) colonoscopy were similar (p=0.30). Presenting symptoms, colonoscopic findings, treatment details, and response to therapy were recorded by medical chart review.
Results: 10/50 (20%) patients showed complete resolution of both collagen thickening and LP inflammation after treatment. An additional 14 patients (28%) showed partial improvement in collagen thickness (7 with improved LP inflammation and 7 without). LP inflammation improved in an additional 7 (14%) patients without any resolution of collagen thickness. A significant reduction in max. collagen thickness (p=0.05), and both mean (p=0.007) and max. (p=0.002) IEL count was noted after treatment.
Clinical response following therapy was significantly associated with resolution of LP inflammation (p=0.001) and eosinophilic infiltration (p=0.008). Max. collagen thickness after treatment increased by 0.17 µm in patients with no clinical response (n=8), decreased by 5.2 µm in patients with partial response (n=20), and decreased by 14.0 µm in patients with complete response (n=16) but this difference did not reach statistical significance (p>0.05). Use of steroids did not correlate with clinical response or histologic resolution (p=0.48).
Conclusions: Subepithelial collagen thickening in CC is reversible, and a subset (20%) of patients show complete histologic resolution after treatment. Resolution of LP inflammation, but not collagen thickness, is significantly associated with clinical response.
Category: Gastrointestinal

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 86, Monday Morning


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