[729] Lymphocytic Colitis: Effect of Therapy on Histologic Findings

Sergey M Pyatibrat, Robert M Najarian, Jeffrey D Goldsmith. Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA

Background: Lymphocytic colitis (LC) is a distinct form of microscopic colitis characterized by a chronic, profuse, watery diarrhea that shows a endoscopically normal appearance; the salient histologic finding is intraepithelial lymphocytosis (IELs). The impact of therapy on the histology has not been thoroughly investigated.
Design: Inclusion criteria required a clinicopathologic diagnosis of LC with index and follow-up biopsies including symptom and medication history relevant to the treatment/diagnosis of LC. Histologic features that were studied included number of surface IELs / 100 colonocytes, presence of chronic changes, acute inflammation, extent of lamina propria expansion by chronic inflammation, degree of surface epithelial damage and site of biopsy (left v right colon).
Results: 228 patients with LC were found from 1/1998-1/2009. Of these, 47 had diagnostic and follow-up biopsies and 21 of these patients had sufficient clinical follow-up for study inclusion. Patients were predominantly female (F:M 18:3) with an average age of 52±15 years at diagnosis. Based on clinical data, patients were divided into two groups.
The first group (8pts) had complete symptomatic resolution. They had, on average, 54±14 IELs on diagnostic biopsy and 12±4 IELs on follow-up biopsy. Patients clinically improved without intervention(3pts), by following a gluten-free diet(1pt), and with discontinuation of rofecoxib(1pt); the remaining patients were treated with medications known to be efficacious in LC.
The second group (13pts) had persistent symptoms. They had, on average, 62±13 IELs on diagnostic biopsy. These patients were subdivided into two subgroups based on histologic follow-up. Subgroup A (4 patients; mean 66±11 IELs), despite persistent symptoms, did not have histologic findings consistent with LC on a follow-up biopsy (mean 14±3 IELs). Subgroup B (9 patients) had no significant change in the number of IELs from the diagnostic (61±13 IELs) to follow-up biopsy (58±10 IELs). All 13 patients in the second group were treated with anti-LC medications. The remaining histologic and clinical parameters, including medication type, did not correlate with symptomatic or histologic improvement.
Conclusions: Based on this preliminary study, complete histologic resolution correlates with symptomatic improvement in a substantial subset of patients with LC; a minority of patients show a discordance between the histologic appearance and presence of diarrhea. The type of anti-diarrheal medication does not seem to affect the histology of follow-up biopsies.
Category: Gastrointestinal

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 106, Monday Morning


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