Fig. 3.

Histology of angiosarcoma in the right external iliac vein. a Magnified image of the tumor. Hematoxylin and eosin staining (b) and Elastica van Gieson staining (c) of (a). Although the vessel wall of the right internal iliac artery (asterisk) was intact, collagen fiber (red fiber in c) and elastic fiber (black fiber in c) around the right external iliac vein were degenerated or disrupted (arrow in c), and spindle-shaped atypical cells were observed on both intraluminal and extraluminal area. Scale bar, 5 mm. d‒f Histological images of tumor cells. Tumor cells were spindle-shaped with irregular nuclei (d). The tumor cells were positive for CD31 (e) and ERG (f) by immunohistochemical analysis. Scale bar, 50 μm.