The undisturbed extension of vessels through an area of abnormal hepatic signal intensity on magnetic resonance (MR) images or abnormal attenuation on computed tomographic (CT) scans has been used as evidence of benign focal fatty infiltration and malignant hepatic neoplasms. Five cases are described in which either portal or hepatic veins extended through a hepatic lesion without evidence of appreciable mass effect, occlusion, or displacement of the vessels. These pathologically proved malignancies included hepatic lymphoma, metastatic melanoma, and metastatic adenocarcinoma.