[Pathology of hepatocellular carcinoma]

The discovery of alpha-fetoprotein and hepatitis B virus related antigens, and the development of diagnostic techniques in the past decade brought a new epoch in the study of hepatocellular carcinoma (HCC). Therefore, pathology of HCC should be re-investigated in accordance with the development of clinical aspects. In this paper, we have described the pathology of HCC based on both autopsy and surgical materials with special reference to angioarchitecture, unusual tumor growth, and histological growth pattern of HCC. Primary tumor, tumor thrombi in the portal vein and the hepatic vein, and intrahepatic metastasis receive arterial blood supply through arterial tumor vessels deriving from the hepatic artery. Unusual tumor growths, such as intrabile duct and intra-atrial tumor growths, have become relatively common, and tumor casts in the bile duct and the right atrium also receive arterial blood supply through arterial tumor vessels. histological growth pattern of HCC can be classified into three types; sinusoidal type, replacing type, and pseudoencapsulated type. The frequency of remote metastasis is different in each type.