Granulomatous interstitial nephritis associated with Primary Sjögren's syndrome.

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by lymphocytic and plasmacytic infiltration of the exocrine glands. Tubulointerstitial nephritis (TIN) is the most common type of renal involvement in pSS. However, clinically significant renal involvement is uncommon. Granulomatous interstitial nephritis (GIN) is a rare histopathological entity characterized by the presence of granulomas against a background of interstitial inflammation. GIN is not a typical and commonly seen form of TIN in pSS. Herein, we report on a patient who was concurrently diagnosed with pSS and GIN and was treated successfully with rituximab (RTX). pSS should be considered in the differential diagnosis of GIN, and RTX may be a good option in the treatment of this patient group.