Characteristics of diffuse large B‐cell lymphoma in patients with primary Sjögren's syndrome

AIM: Patients with primary Sjögren's syndrome (pSS) have an increased risk of developing diffuse large B‐cell lymphoma (DLBCL), which is an aggressive and heterogeneous non‐Hodgkin lymphoma. This study aimed to characterize DLBCLs in patients with pSS. METHOD: We identified 18 patients with DLBCL and pSS over a 22‐year period. Based on the 2016 WHO guidelines, we characterized DLBCL based on immunohistochemical tests using a broad panel of antibodies, and an Epstein‐Barr virus (EBV) test using in situ hybridization. RESULTS: The median time from initial pSS symptom onset to the DLBCL diagnosis was 20.5 years and the median time from the pSS diagnosis until the DLBCL diagnosis was 14 years. After the lymphoma diagnosis, the median overall survival was 3 months (range: 0‐212 months) and the 5‐year overall survival rate was 37.5%. Thirteen DLBCLs were re‐classified as DLBCL, not otherwise specified (NOS) in nine cases; EBV‐positive DLBCL, NOS in two cases; and T‐cell/histiocyte‐rich large B‐cell lymphoma in two cases. Five cases of DLBCLs were not re‐classified because their EBV status was unknown. The Hans algorithm, which uses a combination of staining for CD10, BCL6, and MUM1, was used to classify the DLBCLs into the germinal center B‐cell (GCB) subtype for three cases and the non‐GCB subtype for nine cases. CONCLUSION: These results indicate that DLBCL tends to occur late in pSS cases and is mainly related to the non‐GCB subtype of DLBCL.