[An elderly case of ANCA-positive membranous nephropathy].

We report a rare case of nephrotic syndrome in an elderly woman with positive antineutrophil cytoplasmic antibody(ANCA). The patient was 81 years of age and had a history of interstitial pneumonia. She was diagnosed rheumatoid arthritis(RA) at admission. Rapidly progressing renal damage was found with mild microscopic hematuria and positive ANCA. The renal biopsy findings indicated membranous nephropathy. Neither gold nor anti-rheumatic drugs had been previously administered. She may have had an RA-specific membranous nephropathy. Crescentic formation was not clear. With hematuria, the leukocyte infiltration in the capillary lumen and the change in epithelial cells of Bowman's capsules would be histological findings suggesting ANCA-associated nephritis. This is a rare report on membranous nephropathy in an RA patient with ANCA-associated nephritis.