Fibrillary glomerulonephritis: presenting as crescentic glomerulonephritis causing rapidly progressive renal failure.

We report an unusual case of fibrillary glomerulonephritis (FGN) presenting as rapidly progressive renal failure and extensive crescent formation along with linear staining of capillary walls of the glomeruli on immunofluorescence, mimicking anti-glomerular basement membrane (anti-GBM) antibody-mediated disease. Laboratory results for circulating anti-GBM antibodies were negative. The subsequent electron microscopic findings were that of presence of electron-dense deposits in the glomerular mesangium and capillary walls, comprising of non-branching fibrils with an average diameter of 16 nm consistent with a diagnosis of FGN. This case illustrates the crucial role of electron microscopy in differential diagnosis of crescentic glomerulonephritis.