Fibrillary Glomerulonephritis in Primary Sjogren's Syndrome: A Rare Cause of Renal Failure

Renal involvement in primary Sjogren's syndrome (pSS) varies in severity and prevalence. Although previously felt to be uncommon, kidneys can be involved in 25% to 30% of pSS patients. Fibrillary glomerulonephritis (FGN) is a rare primary glomerular disease that can occur in association with another autoimmune condition or malignancy. The diagnosis relies on renal biopsy findings of haphazardly arranged fibrils in all glomerular compartments and distinction from other forms of fibrillary glomerulopathies such as renal amyloidosis and immunotactoid glomerulopathy. FGN responds poorly to immunosuppressive therapy and has a poor prognosis. Here, we describe a case of FGN in a patient with asymptomatic pSS. We describe the diagnostic work-up, clinical course, treatment utilized, and 1-year follow-up. There is one other case in the literature of FGN in a patient with pSS. The rarity of this association and distinction of FGN from other forms of renal involvement in pSS is important as it impacts therapy and prognosis. The case highlights electron microscopy findings in FGN and poor prognosis.