Metastatic liver tumor with tumor thrombi of the portal vein.

Tumor thrombi of the portal vein are an important prognostic indicator for primary hepatocellular carcinoma (hepatoma), and their presence is a major criterion in differentiating intrahepatic tumors. We report four cases of metastatic liver tumors with tumor thrombi, one a gastric tumor and the others colorectal cancers, two of which were difficult to differentiate from hepatoma. The angiographic features of hepatoma are reviewed and differentiation between the two is discussed. Angiography showed the vessels of metastatic liver tumors to be of fine to mixed types. Chaotic vessels and pooling are characteristic of hepatomas, and dense tumor stains are observed only in hepatomas. The mean survival period after angiography was 3.8 months, and the prognosis was not favorable in patients having "thread-and-streak" sign on angiography.