Primary tumors of the liver.

Primary tumors of the liver that are of clinical significance are rare. Ninety-five percent of such lesions when encountered will be malignant and only 5% will be benign. Malignant primary hepatic lesions represent 2% to 3% of primary cancers encountered in the United States. Hepatocellular carcinoma constitutes 90% of malignant liver primaries in the adult. Seventy-five percent of cases are associated with cirrhosis of the liver and patients with hepatitis B infection have a 33- to 200-fold excess risk for this malignancy. Cholangiocarcinoma represents 5% to 10% of hepatic primary malignancies while hepatoblastoma is distinctly uncommon in adults. Treatment is primarily surgical, and resectability is limited by the presence of cirrhosis and spread of the tumor within and outside of the liver. Of the benign liver tumors, the liver cell adenoma seem to be associated with oral contraception and have a proclivity for intraperitoneal hemorrhage, especially during pregnancy. Focal nodular hyperplasia is a tumor-like condition that also may be associated with oral contraception. This article describes five cases, two of which had quite unique presentations.