Lymphocytic colitis: pathologic predictors of response to therapy.

Although the presence of intraepithelial lymphocytosis with surface epithelial damage is a unifying feature of lymphocytic colitis, there are nonclassical features that create morphologic heterogeneity between cases. Limited data on the significance of these secondary histologic features are available. Cases of lymphocytic colitis diagnosed between 2002 and 2013 were identified using the Research Patient Data Registry of a tertiary referral center. Diagnostic biopsy slides were reviewed and evaluated for histologic features of lymphocytic colitis. Clinical data including type of therapy and response to treatment were collected. χ2 Test (or Fisher exact test) and logistic regression analysis were used where appropriate. Thirty-two cases of lymphocytic colitis with complete clinical data and slides available for review were identified. The mean age was 56.4 years, and the female-to-male ratio was 3:2. Eleven patients improved with minimal intervention (group 1), 14 patients responded to steroid therapy (group 2), and 7 patients responded to mesalamine, bismuth subsalicylate, and/or cholestyramine therapy (group 3). Histologic differences in the characteristics of the subepithelial collagen table (P = .018), the severity of lamina propria inflammation (P = .042), and the presence of eosinophil clusters (P = .016) were seen between groups 2 and 3. Patients in group 1 were more likely to have mild crypt architectural distortion in their biopsies than patients in groups 2 and 3. Lymphocytic colitis is a heterogeneous disease, and the evaluation of histologic factors may help identify various subtypes and predict therapy response.