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

Fibrillary glomerulonephritis (FGN) is characterized by deposition of non-amyloidotic 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.