Introduction

Liver cancer is the eighth most common cancer in the world, and is particularly frequent in certain regions of Africa, China, Japan and East Asia. Unless otherwise specified, the following discussion relates to tumors of the liver cells (hepatocellular carcinoma).

Histology, classification and diagnosis

In considering the etiology of primary cancer of the liver, three major types may be considered:

Hepatocellular carcinoma (HCC) is by far the most common type, arising directly from liver cells. There are several histological subtypes which do not appear of etiological significance. A rare type of solitary hepatoma (both benign and malignant) arises in an apparently undamaged liver. HCC is frequently associated with severe liver damage and cirrhosis, especially in Africa. Liver cirrhosis may be considered as a premalignant condition; the risk, however, varies with type and cause of the cirrhosis being much higher in African macro-nodular cirrhosis.

Cholangiocarcinoma or tumors of the intra-hepatic bile ducts form less than 10% of liver tumors in industrial countries. They are, however, common in South East Asia where they are usually associated with certain parasites.

Miscellaneous tumors arising from the endothelial cells, connective tissue or reticular cell elements of the liver, e.g. angiosarcomas and rare embryonal cancers (hepatoblastoma).