Fibrillary glomerulonephritis (FGN) is a rare primary glomerular disease. Most previously reported cases were idiopathic. To better define the clinical-pathologic spectrum and prognosis, we report the largest single-center series with the longest follow-up. The characteristics of 66 FGN patients who were seen at Mayo Clinic, Rochester, between 1993 and 2010 are provided. The mean age at diagnosis was 53 years. Ninety-five percent of patients were white, and the female:male ratio was 1.2:1. Underlying malignancy (most commonly carcinoma), dysproteinemia, or autoimmune disease (most commonly Crohn's disease, SLE, Graves' disease, and idiopathic thrombocytopenic purpura), were present in 23, 17, and 15% of patients, respectively. Presentation included proteinuria (100%), nephrotic syndrome (38%), renal insufficiency (66%), hematuria (52%), and hypertension (71%). The most common histologic pattern was mesangial proliferative/sclerosing GN followed by membranoproliferative GN. During an average of 52.3 months of follow-up for 61 patients with available data, 13% had complete or partial remission, 43% had persistent renal dysfunction, and 44% progressed to ESRD. The disease recurred in 36% of 14 patients who received a kidney transplant. Independent predictors of ESRD by multivariate analysis were older age, higher creatinine and proteinuria at biopsy, and higher percentage of global glomerulosclerosis. Underlying malignancy, dysproteinemia, or autoimmune diseases are not uncommon in patients with FGN. Prognosis is poor, although remission may occur in a minority of patients without immunosuppressive therapy. Age, degree of renal impairment at diagnosis, and degree of glomerular scarring are predictors of renal survival. © 2011 by the American Society of Nephrology
