Hepatocellular carcinoma: clinicopathological aspects

The histopathology and clinical picture of hepatocellular carcinoma (HCC) varies between individual patients and regions. These variations are perhaps due to differences in the genetic alterations that precede hepatocarcinogenesis. In this study, the clinicopathological features of HCC were compared between southern African blacks and Japanese, indicating large differences in the frequency of underlying cirrhosis, grade of cancer cell differentiation and clinical course. Intra-abdominal bleeding and febrile, rapidly progressive HCC are more common among blacks. Such a difference is accounted for, in part, by frequent encapsulation of the tumour which is well differentiated, and grows slowly in an expanding fashion in Japan. Encapsulated HCC was not seen among the black patients studied. Other distinct clinicopathological types discussed in this paper include diffuse-type HCC which is usually caused by multiple portal spread occurring almost simultaneously; the clinical course is fulminant. Sclerosing carcinoma is frequently associated with hypercalcaemia in the United States, but not in Japan. Fibrolamellar carcinoma is nearly non-existent in Asia, whereas it is common among young adults in the West. Its prognosis is generally better than ordinary HCC. Hepatocellular carcinoma has a strong propensity to invade vessel and duct systems. Portal invasion does not produce distinct clinical signs although it may aggravate portal hypertension. Patients with tumour occlusion in the major portal vein may give rise to ischaemic hepatitis when blood pressure drops suddenly in the preterminal stage. Liver parenchyma develops submassive necrosis and clinically there is an acute rise in alanine aminotransferase (ALT). Invasion into a major hepatic vein and the inferior vena cava also occurs, but less frequently compared with portal invasion. The patient can live even with a tumour thrombus in the atrium crossing the tricuspid valves. Intraductal invasion causes acute jaundice as well as an occasional haemobilia with pain. We recently found that a distinct pathological type called 'extrahepatic growth' or 'pedunculated HCC' develops as a result of fusion of right-sided adrenal metastasis of HCC and the liver, perhaps through the 'adreno-hepatic fusion' which is rather common in cirrhotic livers.