Diffuse Crescentic Fibrillary Glomerulonephritis with a Favorable Outcome.

Fibrillary glomerulonephritis (FGN) is an uncommon form of kidney disease that can occasionally present in a diffuse crescentic variant.This may sometimes mimic anti-glomerular basement membrane (anti-GBM) disease as the immunofluorescence can have a pseudo-linear appearance.The prognosis of diffuse crescentic FGN is considered grim with virtually all patients either presenting with or progressing to end stage kidney disease.We present a case of a 31-year-old female who presented with a rapidly progressive glomerulonephritis with diffuse J o u r n a l P r e -p r o o f crescentic disease on light microscopy.Initially, there was a suspicion for anti-GBM disease, however electron microscopy and immunohistochemistry confirmed FGN.Notably, she responded well to aggressive immunosuppressive therapy with steroids and intravenous cyclophosphamide, and maintenance therapy with tacrolimus and mycophenolate mofetil.She had significant improvement in renal function over the following year.This case highlights both a diagnostic challenge in crescentic FGN and also shows that a favorable outcome is sometimes possible with early and prompt immunosuppression.