Crescentic glomerulonephritis complicating idiopathic membranous glomerulonephropathy.

We describe the course of a patient with multiple rectal abscesses and progressive renal dysfunction. A renal biopsy demonstrated a membranous glomerulopathy associated with extensive crescent formation. No underlying cause for the glomerulonephritis could be identified and, specifically, the anti-GBM antibody present in other similar cases was not found. There appears to be a subset of patients with membranous glomerulopathy in whom crescents develop with rapid loss of renal function. Anti-GBM antibody is not necessary in the pathogenesis of this lesion.