A Case of Membranous Glomerulonephritis with Superimposed Anti-Neutrophil Cytoplasmic Antibody-Associated Rapidly Progressive Crescentic Glomerulonephritis

Idiopathic membranous glomerulonephritis (IMGN) is commonly diagnosed in adults with proteinuria. Rapid deterioration of renal function is a rare complication of IMGN, except when accompanied by renal vein thrombosis, malignant hypertension, or other underlying disease, including lupus nephritis. Here, we present a case of rapid deterioration of renal function in a patient with MGN superimposed with anti-neutrophil cytoplasmic antibody (ANCA)-associated rapidly progressive crescentic glomerulonephritis (RPGN). Overall, about 20 cases of MGN with ANCA-associated RPGN have been reported. This case of biopsy-proven MGN with ANCA-associated RPGN is the first to be reported in Korea.