This article details the diagnosis and imaging of primary and secondary neoplasms of the liver. Benign conditions that can mimic malignancy are also discussed, such as focal nodular hyperplasia and adenoma. Considerable attention is given to hepatoma, which is the most common primary hepatic tumor in the United States. The roles of magnetic resonance imaging, computed tomography, and ultrasound are evaluated, with recommendations for their effective use. Pitfalls in imaging related to posttreatment changes and unusual patterns of metastatic disease are illustrated.KEYWORDS: Cancer, liver, hepatoma, imaging, metastasisObjectives: Upon completion of this article, the reader should (1) know the primary hepatic neoplasms and the major benign conditions that can mimic malignancy, and (2) understand the uses of ultrasound, computed tomography, and magnetic resonance imaging in diagnosing hepatic tumors. Accreditation: Tufts University School of Medicine (TUSM) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Credit: TUSM designates this educational activity for a maximum of 1 Category 1 credit toward the AMA Physicians Recognition Award. Each physician should claim only those credits that he/she actually spent in the activity.
PRIMARY LIVER MALIGNANCIES
HepatomaThe most common malignant primary liver tumor in U.S. adults is hepatocellular carcinoma (HCC) or hepatoma, which arises from hepatocytes.1 This represents 70 to 80% of all primary liver tumors. In the western world, up to 75% of the people who develop hepatoma also have cirrhosis. Still, hepatoma is a relatively uncommon tumor in the United States, comprising only 2% of all reported malignancies. In the rest of the world it is more common and is the third leading cause of cancer-related mortality. In the United States, HCC is more common in men than women and is typically seen in older patients with cirrhosis.
2,3Infection with either hepatitis B or hepatitis C is associated with an increased risk of cirrhosis and liver cancer. Chronic hepatitis B carriers have a 100-fold higher risk of developing HCC than the general population. In one study in Taiwan, hepatitis B virus surface antigen (HBsAg) chronic carriers had a risk of HCC 217 times that of a noncarrier. 4 In the same study, 51% of deaths of HBsAg carriers were caused by liver cirrhosis or HCC as compared with 2% of the general population.Hepatitis B is a DNA tumor virus. The oncogenic mechanism is incorporation of viral DNA into the host genome of infected hepatocytes by reverse