Membranous nephropathy with crescents.

Membranous nephropathy is a common cause of nephrotic syndrome in adults and can be primary or secondary to systemic lupus erythematosus, chronic infection, or drugs. Rapid decline in renal function in patients with membranous nephropathy may be due to renal vein thrombosis, malignant hypertension, or an additional superimposed destructive process involving the renal parenchyma. Crescents are rare in primary membranous nephropathy and thus suggest another underlying disease process, such as combined membranous and focal or diffuse lupus nephritis. However, in some patients with membranous nephropathy and crescents, the crescentic lesion may be due to a distinct, separate disease process, such as anti-glomerular basement membrane antibodies or anti-neutrophil cytoplasmic antibodies-related pauci-immune glomerulonephritis. Here we describe a case with such renal biopsy findings, review previous reported cases, and discuss possible implications for pathogenesis of the coexistence of these lesions.