Congo red-negative amyloidosis-like glomerulopathy: report of a case.

An elderly patient who had nephrotic syndrome for many years was found to have mesangial expansion and thickening of the glomerular capillary basement membranes (GBMs) on light microscopy. Electron microscopy (EM) showed tubular structures measuring 24 to 27 nm in the mesangium and the subepithelial areas. Congo red staining for amyloid was negative. This case represents another instance of congo red-negative amyloidosis-like glomerulopathy.