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

Abstract

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.

Keywords: Anti-neutrophil cytoplasmic antibody-associated vasculitis; Antibodies; Glomerulonephritis; Membranes.

FIG. 1. The glomeruli were segmentally involved with epithelial crescentic proliferation. The remaining glomerular capillaries appeared thickened (Periodic acid-Schiff stain, ×400).

FIG. 2. (A) Direct immunofluorescence (IF) revealed granular IgG deposits along the capillary walls (anti-human IgG, ×200). (B) Direct IF revealed granular IgA deposits along the capillary walls (anti-human IgA, ×200). (C) Direct IF revealed granular C3 deposits along the capillary walls (anti-human C3, ×200).

FIG. 3. The glomerular capillary walls showed epimembranous (long arrow) and intramembranous (short arrow) electron-dense deposits. The overlying epithelial foot processes were diffusely effaced (uranyl acetate and lead citrate, ×4,000).