Fig. 4

Microscopic findings of the mass lesion. a The tumor shows a circumscribed tumor composed of scattered and dilated blood space (hematoxylin and eosin stain; original magnification, ×20). b Stained specimen shows blood vessels lined by normal endothelial cells and round to ovoid cells with round nuclei and acidophilic cytoplasm (hematoxylin and eosin stain; original magnification, ×200). c Tumor cells are smooth muscle actin–positive (original magnification, ×200)