Diffuse hepatic angiosarcoma with a portal venous supply mimicking hemangiomatosis

We report a case of diffuse hepatic angiosarcoma. Dynamic computed tomography (CT) showed gradual contrast enhancement and homogeneity in the late phase. The tumor was homogeneously hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging, mimicking hemangiomatosis. An angiogram demonstrated intrahepatic arterial encasement, which suggested malignancy. The portal venous supply to the tumor was demonstrated by CT during arterioportography. This probably reflected the continuous infiltration of atypical cells into the dilating sinusoids and may also suggest malignancy.