Fig. 2

Histopathology of (a-f) renal biopsy and (g-i) nephrectomy specimens. H&E staining showed a mild glomerular hypercellularity and b platelet thrombi within capillary loops and the mesangium. c PAS staining demonstrated increased matrix production glomeruli without sclerosis. d Immunofluorescent antibody staining showed fibrinogen staining within glomerular capillaries. Electron micrographs (EM) demonstrated e a thrombus including several platelets (small arrows) and erythrocytes (asterisks) within a glomerular capillary (endothelial cell nuclei labeled with large arrows) f a glomerular capillary with adjacent podocyte foot process effacement. Six months after initial presentation the patient underwent bilateral nephrectomy due to the risk of Wilms tumor development. g Gross examination of the patient’s kidneys at the time of nephrectomy revealed small, sclerotic kidneys, which had a combined weight of only 30.6 g (average weight for age is 71 g). h H&E staining demonstrated a glomerulus undergoing mesangial sclerosis and an adjacent arteriole with “onion skinning” appearance due to intimal and mural thickening. i. PAS staining showed globally sclerotic glomeruli and arteriolar lumenal narrowing with intimal and mural thickening