Histopathologic analysis confirms disseminated platelet- and VWF-rich aggregates in multiple organs. Tissue sections of kidney, heart, brain, lung, and spleen (indicated above the panel) were prepared and stained as shown to the right; hematoxylin and eosin (H&E), immunohistochemical staining for platelet antigen CD61 and for VWF as well as a Martius yellow, Brilliant crystal scarlet 6R, and Soluble blue (MSB) stain for fibrin. The MSB stain colors both muscle and fibrin bright red and erythrocytes yellow/orange, and nuclei and connective tissue stains blue/purple. Arrows indicate thrombi, and arrowheads indicate open vessels. Original magnification (all panels) ×400.