Light micrograph showing collapsing FSGS

Light micrograph showing collapsing glomerulosclerosis with few open loops in the sclerotic areas (long arrows); these findings are characteristic of HIV nephropathy but can also be seen in idiopathic disease. The degree of collapse can be appreciated by the openness of Bowman's space. Vacuolization and crowding of the glomerular epithelial cells (short arrows) is also frequently seen and reflects the primary epithelial cell injury in this disorder.

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).