Fibrillary glomerulonephritis: A report of 2 cases with extensive glomerular and tubular deposits

Deposition of nonamyloid fibrillary material in glomeruli is well known. It is, however, unusual to find these fibrils in the tubular basement membran es and unprecedented to have fibrils of different sizes in the same patient . We present 2 cases with nephrotic range proteinuria with evidence of rena l insufficiency. In both cases, strong, polyclonal immunoglobulin (Ig)G wit h C3 deposits were shown in the glomeruli and along tubular basement membra nes. Ultrastructurally, the first case had 28-nm fibrils deposited extensiv ely in the glomeruli and along tubular basement membranes. The second case had 30-nm fibrils in the glomeruli and 15-nm fibrils in the tubules. In bot h cases, the fibrils did not react with the regular amyloid stains. These f indings are used to support the view that fibrillary glomerulopathy is not a disease, but rather the morphologic expression of an etiologically divers e group of diseases as yet incompletely defined. Copyright (C) 2001 by W.B. Saunders Company.