Typical examples of renal histopathology in patients with TMA. (A) Microaneurysm (arrow), silver stain (original magnification, ×100). (B) Fibrin microthrombi in glomerular capillaries (arrow), phosphotungstic acid-hematoxylin (PTAH) stain (original magnification, ×100). (C) Fibrin microthrombi in an artery (arrow), PTAH stain (original magnification, ×40). (D) Fibrin microthrombi in an arteriole (arrowhead) and the vascular pole of the glomerulus (arrow), PTAH stain (original magnification, ×100). (E) Organizing microthrombi with recanalization (arrow), silver-stained sample (original magnification, ×100). (F) Arteriolar onion ring (arrow), silver stain (original magnification, ×60).