Fibrillary glomerulonephritis with hypocomplementemia.

A 59-year-old man was referred for evaluation of nephrotic syndrome. The patient was diagnosed to have rheumatoid arthritis and had been treated for 10 years. Renal biopsy showed mesangial proliferation with small nodular formations, which were determined as fibrillary deposits (average diameter: 20 nm) by electromicroscopy. Congo-red stain was negative. The laboratory findings revealed hypocomplementemia and lambda type of Bence-Jones protein in urine without other systemic diseases including multiple myeloma. Immunosuppressive therapy did not attenuate the nephrotic-range proteinuria. Such a case of fibrillary glomerulonephritis with hypocomplementemia is rare.