The epidemiology and morphology of primary malignant liver tumors.

The ubiquitous problem of cirrhosis may be complicated by the development of primary liver cell carcinoma, with rates of incidence so high in certain parts of the world as to make it a candidate for the most common cancer in humans. When cirrhosis reaches the macronodular stage, the risk of developing liver cell carcinoma increases, and at this point liver cell dysplasia may be seen in biopsy. Alcoholics, who classically have a micronodular cirrhosis, may attain the macronodular pattern through better clinical management, abstinence, and longer survival. Hepatitis B-related cirrhosis, on the other hand, is most often macronodular. Recent DNA hybridization studies strongly favor a viral role in oncogenesis, and this possibility is supported by the serologic and epidemiologic evidence complied in the last decade. Liver cell malignant tumors tend to recapitulate the characteristics of normal liver, namely, growth in cords, uniformity of cytologic appearances, and bile production, but also present distinctive histologic and immunohistochemical patterns that are unique to a malignant liver cell population. The other primary malignant tumors of the liver, arising in bile ducts, blood vessels, and mesenchymal elements, all carry their individual epidemiology and morphology, but in general invoke, as does liver cell carcinoma, the concept of a series of step by step cell-carcinogen and cell-carcinogen interactions by which normal cells give rise to malignant populations.