Paraneoplastic polymyositis associated with crescentic glomerulonephritis.

A female concurrently developed polymyositis (PM), lung cancer, and nephrotic range proteinuria. Renal biopsy revealed crescentic glomerulonephritis. Pathology of lung cancer was proved to be adenocarcinoma. After surgical treatment of lung cancer, the symptoms of PM-associated crescentic glomerulonephritis disappeared. PM is associated with a higher risk of malignancy, though renal involvement in patients with PM is thought to be uncommon. In patients with PM, there have been few reports concerning the coexistence of glomerular disease, including crescent glomerulonephritis. Herein we report a case of crescentic glomerulonephritis-associated PM that was successfully treated after the surgical removal of lung cancer. We consider that such association of PM and crescent glomerulonephritis is rare in adults. Careful evaluation of underlying malignancy is important. The definite treatment is adequate management of underlying malignancy.