Clinicopathologic characteristics and outcomes of transformed diffuse large B-cell lymphoma in hepatitis C virus-infected patients: A case-control study of 84 patients.

7553 Background: Chronic hepatitis C virus (HCV) infection is associated with development of marginal zone lymphoma (MZL) and diffuse large B-cell lymphoma (DLBCL). Preliminary data showed particular characteristics of HCV-associated DLBCL; such as frequent transformation from indolent lymphomas and aggressive oncologic courses. We studied herein the clinicopathologic characteristics and outcomes of HCV-infected patients (pts) with transformed DLBCL. Methods: In this case control study, the medical records and pathology reports of HCV-infected (cases) and HCV-uninfected (controls) pts with transformed DLBCL seen at our institution (6/2004 - 5/2015) were reviewed. Included pts had a concomitant or a history of a low grade lymphoma. To determine their clinicopathologic characteristics, cases were compared to controls at a ratio of 1:3. To determine predictors of oncologic relapse, we compared pts with DLBCL relapse after first line chemotherapy to those who did not relapse in univariate and logistic regression analyses. Results: Twenty-one cases were compared to 63 controls. Compared to controls, cases were younger (median year age [interquartile range], 54 [49-62] v 62 [53-66], P = .01), had advanced Ann Arbor stages, 3-4 (95% v 76%, P = .05), and upper gastro-intestinal involvement (48% v 25%, P = .05). Immunophenotypically, cases had more CD10-negative B-cells (76% v 43%, P = .008) and CD5-positive B-cells (39% v 7%, P = .004) compared to controls, consistent with an activated B-cell phenotype. A comparison between pts who relapsed after first line chemotherapy (n = 42) and those who did not (n = 40) revealed that having CD5-positive B-cells was the only factor associated with DLBCL relapse in univariate (24% v 6%, P = .03) and multivariate analyses (OR = 10.7, P= .02). Conclusions: HCV-infected pts with transformed DLBCL are younger, present with advanced stages, are more commonly CD5-positive, and have an activated B-cell phenotype, suggesting more frequent transformation from MZL compared to HCV-uninfected pts. The higher frequency of CD5-positive B-cells might explain the higher DLBCL relapses previously described in HCV-infected pts.