Early‐stage splenic diffuse large B‐cell lymphoma is highly associated with hepatitis C virus infection

Splenic marginal zone lymphoma (SMZL) and splenic diffuse large B‐cell lymphoma (DLBCL) are the most common types of lymphomas involving the spleen. Geographic variation in hepatitis C virus (HCV) seroprevalence is characteristic of splenic lymphomas. In Italy, HCV seroprevalence was higher in patients with SMZL and splenic DLBCL than in patients with all types of lymphoma. In Japan, HCV seroprevalence was higher in patients with splenic DLBCL than in patients with all types of lymphoma; however, HCV seroprevalence in patients with SMZL was similar to that in patients with all types of lymphoma. In this study, clinicopathological data of 74 splenic lymphoma cases between 1988 and 2011 collected from the Department of Pathology at National Taiwan University Hospital were analyzed. Serology for HCV infection was available for 41 cases. Splenic DLBCL and SMZL accounted for 36% ( n  = 27) and 42% ( n  = 31) of splenic lymphomas, respectively. Microscopically, most cases of DLBCL (26/27) presented with circumscribed tumor and most cases of SMZL (28/31) presented with white pulp expansion. HCV seroprevalence in patients with DLBCL and SMZL was 44% and 10%, respectively (7/16 vs. 2/20, p  = 0.020). The pattern identified in this study is closer to that in Japan than in Italy. HCV seroprevalence in patients with early‐stage (I/II) and late‐stage (III/IV) DLBCL was 100% and 10%, respectively (6/6 vs. 1/10, p  < 0.001). Early‐stage DLBCL is clinically considered a form of primary splenic lymphoma rather than a systemic lymphoma with splenic involvement. High HCV seroprevalence in patients with early‐stage DLBCL suggests a role of HCV in the pathogenesis of primary DLBCL.