Systemic non-amyloidotic fibril deposition disease: A probable variant form of fibrillary glomerulonephritis

Fibrillary glomerulonephritis (FGN) is characterized by deposition of nonamyloidotic fibrillary material in glomeruli, and most patients with the disease show heavy proteinuria and hematuria, and progress into end-stage renal failure. We report a 62-year-old woman with FGN who showed mild proteinuria without hematuria and developed rapidly progressive renal failure requiring hemodialysis. Renal biopsy showed severe tubulointerstitial injury associated with non-amyloidotic fibrillary deposits in the tubular basement membrane, interstitium and vessel walls, in addition to glomeruli. The patient died from liver abscess 1 year after the introduction of hemodialysis. Postmortem examination showed the presence of non-amyloidotic fibrillary deposits arranged in tightly packed electron-dense and bundle-shaped structures in many organs. These findings suggest systemic non-amyloidotic fibril deposition in FGN.