Fibrillary glomerulonephritis

Light micrograph in fibrillary glomerulonephritis shows diffuse expansion of the mesangium by amorphous, acellular material (arrows). Electron microscopy and Congo red staining are necessary to distinguish this light microscopic appearance from amyloidosis or light chain deposition disease.

Light micrograph of a normal glomerulus. There are only one or two cells per capillary tuft, the capillary lumens are open, the thickness of the glomerular capillary wall (long arrow) is similar to that of the tubular basement membranes (short arrow), and the mesangial cells and mesangial matrix are located in the central or stalk regions of the tuft (arrows).