Figure 1.

Pathologic findings. (A) A glomerulus with collapsing FSGS exhibits global wrinkling and retraction of the glomerular basement membranes and diffuse swelling and proliferation of overlying visceral epithelial cells (Jones methenamine silver). (B) In this glomerulus with collapsing FSGS, some of the podocytes are detached from the glomerular basement membrane and lie free within the urinary space (periodic acid Schiff). (C) On ultrastructural evaluation, visceral epithelial cells exhibit microvillous transformation and complete foot process effacement. An endothelial TRI is present. (D) At high magnification, an endothelial TRI is seen. Magnifications: ×400 in A and B; ×5000 in C; ×8000 in D.