Fig. 2

Microscopic examination with low (× 50) and high (× 400) power photograph. The low power photograph showed the tumor tissue was composed of tortuous and anastomotic capillary-sized vessels (A). The high power photograph showed wall of vessel was lined by spindle or oval endothelial cells, some of which protrude into the cavity. Additionally, the tumor cells were with evenly distributed euchromatin, typically bland appearing, and mitoses were scarce (B). Immunohistochemical studies showed the tumor cells expressed endothelial cells markers, which showed CD31 (C) and CD34 (D) were positive