Chapter 49. Liver Neoplasms

The increased used of imaging modalities—ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI)—over the past few decades has led to an increase in the detection of hepatic masses. In the noncirrhotic patient or in patients with no history of extrahepatic malignancies, most of these lesions are benign. Diagnosis is often made on the basis of radiographic appearance, and only in rare equivocal cases is histologic analysis required. In patients with cirrhosis or those with chronic hepatitis B infections, the detection of a hepatic mass often raises suspicion of a hepatocellular cancer, and frequently additional diagnostic (including histologic) and therapeutic interventions are necessary.

Liver lesions are often classified on the basis of appearance (cystic or solid) and histologic composition (hepatocellular or biliary). They can also be classified based on malignant potential (benign or malignant), and when, malignant, they can be classified based on origin of the cancerous cells (primary or metastatic). In adults, malignant tumors are more common than benign tumors and metastatic lesions account for most forms of liver neoplasms. The differential diagnosis of liver lesions includes benign lesions (eg, hemangioma, focal nodular hyperplasia, adenoma, focal regenerative hyperplasia, simple hepatic cysts, polycystic liver disease, bile ductular cystadenoma, and bile ductular hamartomas) and malignant lesions (eg, primary hepatocellular cancer, cholangiocarcinoma, metastatic tumors, lymphoma).

Essentials of Diagnosis

• Cavernous hemangiomas, focal nodular hyperplasia, hepatic adenomas, and nodular regenerative hyperplasia are the most common benign tumors of the liver.
• Cavernous hemangiomas are usually asymptomatic and can be identified by their classic appearance on CT and MRI.
• Focal nodular hyperplasia is common in young women and can be identified by the presence of a central stellate scar on CT or MRI.
• Hepatic adenomas are common in women of childbearing age, especially after prolonged oral contraceptive use. Because necrosis, hemorrhage, or rupture can occur, they should be surgical excised when identified.
• Nodular regenerative hyperplasia is associated with many systemic illnesses. Patients present with signs of portal hypertension. Radiographic characteristics are nonspecific, and histologic evaluation shows no fibrosis.

In clinical practice the most commonly encountered lesions are cavernous hemangiomas, focal nodular hyperplasia (FNH), hepatic adenoma, and nodular regenerative hyperplasia.

Cavernous Hemangiomas

General Considerations

This is the most common benign lesion of the liver, with a prevalence that ranges from 1% to 20% of the general population. Approximately two thirds of all cavernous hemangiomas are found in the right lobe of the liver, and more than 90% are solitary. More than 80% occur in women. Although lesions can be small (often ≤1 cm), larger lesions, especially those greater than 4 cm (giant hemangiomas), also occur; some can be as ...