Ectopic Germinal Center-Like Structures in Minor Salivary Gland Biopsy Tissue Predict Lymphoma Occurrence in Patients With Primary Sjogren's Syndrome

Objective. To determine risk factors for primary Sjogren's syndrome (SS)-associated lymphoma in a multicenter cohort of patients, with analysis of the predictive power of previously reported risk factors, including the presence of ectopic germinal center (GC)-like structures in minor salivary gland (MSG) biopsy tissue. Methods. One hundred fifteen patients with primary SS were included, and MSG biopsy tissue from these patients was retrospectively examined, focusing on the presence of ectopic GC-like structures. Epidemiologic, clinical, biologic, immunologic, and histologic data were collected at the time of diagnosis of primary SS. Patients with non-Hodgkin's lymphoma (NHL) were compared with those without NHL during the follow-up period, using a Cox proportional hazards multiple regression model. Results. NHL was diagnosed in 8 patients (6.96%), and ectopic GC-like structures in 19 patients (16.5%). The presence of ectopic GC-like structures was associated with a 7.8-fold increased risk of lymphoma occurrence (95% confidence interval [95% CI] 1.73-34.86 [P = 0.0075]). Other independent predictors included a positive cryoglobulin test result (hazard ratio [HR] 7.10, 95% CI 1.74-28.92 [P = 0.006]), male sex (HR 28.73, 95% CI 4.46-144.87 [P = 0.0004]), sensorimotor neuropathy (HR 35.48, 95% CI 5.79-217.39 [P = 0.0001]), and splenomegaly (HR 19.9, 95% CI 4.4-90 [P = 0.0001]). Conclusion. The presence of ectopic GC-like structures in MSG biopsy tissue is associated with the risk of lymphoma in patients with primary SS. These data reinforce the major role of MSG biopsy tissue in primary SS, for the identification a priori of a subgroup of patients with the highest risk of lymphoma.