Pathomorphological study on hepatocellular carcinoma

A study of tumor thrombus of the portal vein

Abstract

Tumor thrombus (TT) was studied histologically in 95 livers bearing hepatocellular carcinoma (HCC). TT was seen in 75 out of the 95 cases (78.9%). Four growth patterns, arbitrarily described as "proliferative type" (35 cases), "necrotic type" (14 cases), "mixed proliferative and necrotic type" (21 cases) and "organized type" (5 cases), were distinguished. Besides tumor extension into the intrahepatic portal vein branches, tumor grows into the periportal capillaries and periductal capillary plexuses as well.
Branches of the hepatic artery are frequently engulfed by the tumor, and it is common to find aneurysmal change and its rupture which cause abnormal shunt formation among the hepatic artery, the portal vein and tumor vessel. Organization of TT appears in the subendothelial space with an increase of collagen fibers. Narrowing and/or obstruction of the portal vein by TT and abnormal shunt formation between the hepatic artery and the portal vein may accelerate a portal hypertension. Thus, risk of rupture of esophageal varices may increase in HCC patients.