Collapsing glomerulopathy is associated with a number of histopathologic findings.
Features seen on light microscopy:
(1) segmental or global glomerular tuft collapse, with wrinkling and folding of the glomerular basement membrane and with occlusion and collapse of capillaries
(2) hyperplasia and hypertrophy of the overlying visceral epithelium (podocytes) which often show protein droplets (reabsorption droplets)
(3) variable segmental or global sclerosis when advanced
Features seen on immunofluorescence:
(1) no or limited nonspecific deposits
Features seen on electron microscopy:
(1) wrinkling and collapse of the glomerular basement membrane
(2) hyperplasia and hypertrophy of the podocytes with vacuoles and protein droplets
(3) extensive foot process effacement with loss of podocyte differentiation
(4) no or limited mesangial deposits
(5) variable tubular-reticular inclusions in endothelial cells (seen in HIV-associated nephropathy and SLE)
