In recent decades the incidence of primary liver cancer has significantly increased. According to Weiss (1978), 20 years ago the frequency of primary liver cancer constituted 0–8% of all the pathomorphological studies and 3% of all the malignant tumors. Presently it constitutes 2–3% and 11% respectively (Podymova 1998). The mean primary liver cancer frequency in Russia is currently 6.2 per 100,000 of the population. There are regions where the values are much higher: in the basins of the Irtysh and Ob they constitute 22.5–15.5 per 100,000, cholangiocellular cancer being more often observed there. The development of cholangiocarcinoma is stimulated by parasitic diseases and helminthiases (amebiasis, schistosomiasis, opisthorchiasis and others). The risk of the disease in persons suffering from ulcerative colitis is higher by 10% than in the general population. Cirrhoses do not predispose to the development of cholangiocarcinoma. However, secondary biliary cirrhosis may develop due to tumor obstruction of bile ducts. On the whole it is hepatocellular cancer (HCC) that prevails among primary malignant liver tumors (80% of all ­primary liver cancers). In 60–80% of patients the development of hepatocellular ­cancer is associated with persistence of the viruses of hepatitis A and B. In 80–90% of these patients tumors accompany cirrhosis. Men develop the disease four- to ten-times more frequently than women. Among predisposing factors of hepatocellular cancer there are uncontrolled consumption of alcohol and other regular intoxications leading to cirrhosis.

Metastatic lesion of the liver is observed 20-times more frequently than primary liver tumors. According to different authors, from 77% to 90% of liver metastases are multifocal. Isolated lesion of one of the lobes of the liver (more frequently the right one) is observed in 10–30% of cases. Most often it is tumors of the large intestine (50–75%), pancreas (45–70%), mammary gland (10–60%), cholecyst and extrahepatic bile ducts (50–60%), stomach (20–50%) and lungs (10–40%) that metastasize to the liver. Some rarer localizations of primary tumors metastasizing to the liver are the esophagus, ovary, skin melanoma, prostate and kidneys (Prokop and Galansky 2003).

The predisposing factors of metastatic lesion of the liver are its double blood supply, a developed net of vessels of the microcircular channel, fenestrated basal membrane of sinusoids favoring the penetration of tumor cells and stimulation of tumor growth by local humoral factors.

The most frequent benign liver tumor is hemangioma. According to data obtained by autopsies, the frequency of this tumor ranges from 1% to 7%. Clinical examinations show that it is observed in 2–4% of adults. The main cause of development of liver hemangioma is considered to be associated with taking oral hormonal contraceptives. On the other hand, the dysembryoplastic theory seems to be fairly well-grounded, according to which liver hemangioma occurs in consequence of abnormal development of vessels in the phase of dysembryogenesis (Granov and Polysalov 1999). The second most frequent benign liver tumor is focal nodular hyperplasia. It is observed in patients aged 20–50 and is four- to ten-times more frequent in women. Focal nodular hyperplasia is often detected accidentally during routine diagnostic examinations. It has been established that occurrence of this disease does not depend on taking oral contraceptives.