Figure 3c. Cardiac angiosarcoma. (a) Photomicrograph (original magnification, x4; hematoxylin-eosin stain) shows frondlike projections (arrow) arising from the luminal surface of the angiosarcoma. In this particular section, the right atrial wall is completely replaced by tumor, necrosis, and hemorrhage. (b) Low-power photomicrograph (original magnification, x40; hematoxylin-eosin stain) shows the angiosarcoma (arrows) invading normal right atrial myocardium. (c) Photomicrograph (original magnification, x100, hematoxylin-eosin stain) shows red blood cells clustered together within a vascular channel (arrow) lined with atypical endothelial cells. This appearance is characteristic for angiosarcoma.