Glomerular capillary loops are focally thickened and wrinkled. Rare splits are noted. Foot process fusion is variable. There is a marked increase in mesangial cells and matrix, resuling in segmental glomerular obliteration. Large, granular, subendothelial and mesangial electron-dense deposits are seen. Mesangial interposition is seen in some glomerular lobules. Inflammatory cells and fibrosis are present in interstitial areas.