[698] A Histopathologic Analysis of Ileitis in Pediatric Ulcerative Colitis (UC)

RM Najarian, A Bousvaros, L Ashworth, JD Goldsmith. Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA; Children's Hospital Boston and Harvard Medical School, Boston, MA

Background: So-called 'backwash ileitis' has been described in adults with UC, especially in those with severely active, proximal colon disease. However, no studies have rigorously characterized such changes in pediatric UC patients. This study investigates the prevalence of ileitis in pediatric UC and the potential association with the severity, distribution, and extent of colonic inflammatory changes.
Design: 48 UC patients were identified who had concurrent, pretreatment ileal and colonic endoscopic mucosal biopsies. Each ileal biopsy was then examined for the presence of ulceration, severity of acute inflammation, features of chronic injury, and granulomas. Concurrent colon biopsies were then reviewed similarly to the ileal biopsies. Additionally, the overall extent and geographic distribution of activity and chronicity in the colon was analyzed. Clinical and endoscopic followup were performed by investigators blinded to the histologic results. Patients with endoscopic features of Crohn's disease or those found to have Crohn's disease in the follow-up period were excluded.
Results: 49 ileal biopsies and 320 colon biopsies were reviewed in 48 patients ranging from 3 to 20 years of age (48% female). Ileitis was found in 12 patients (25% of population). Acute inflammatory (AI) changes were the only findings seen in the inflamed ileal biopsies (surface/crypt AI: 10 cases, crypt abscess: 1 case, erosion: 1 case). Pancolitis or subtotal colitis (pancolitis with cecal sparing) was found in 100% of patients with ileitis and 73% of patients without ileitis (p=0.065); distal colonic disease was found in 17% and 34% of patients with and without ileitis, respectively (p=0.322). Active inflammation was noted in the cecum in 84% of patients with ileitis and in 62% of patients without ileitis (p=0.134); the severity of cecal active inflammation was not associated with ileitis. The presence of neutrophilic crypt abscesses or ulceration was found in 42% and 50% of patients with and without ileitis, respectively (p=0.433).
Conclusions: The severity, extent, or distribution of active inflammation in the colon is not associated with the presence of ileitis in these pediatric UC patients. Thus, the proposed mechanism of "backwash ileitis” is likely not the sole mechanism for ileal inflammation in pediatric UC.
Category: Gastrointestinal

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 100, Monday Morning


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