Fig. 1

a An enhanced CT indicated a tumor abutted on the superior mesenteric vein in the level of maximum short-axis diameter (white arrowhead). b Axial view of the CT examination revealed cavernous transformation around the hepatic hilum. c Cranial view of the CT showed serpiginous collateral vessels leading to the intrahepatic portal vein. d Three-dimensional reconstruction image of the CT examination showed that two main collateral vessels (yellow arrowheads) existed around the hepatic portal region, and the superior mesenteric vein, the splenic vein and the portal vein in the pancreas had no sign of tumor invasion (yellow arrows)