Benign Liver Tumors

Hepatocellular adenoma is the most important benign tumor to recognize. It occurs primarily in women of childbearing age, particularly those taking oral contraceptives, possibly via estrogen’s effects (1).

Most adenomas are asymptomatic, but large ones may cause right upper quadrant discomfort. Larger adenomas (typically > 5 cm) may manifest with peritonitis and shock due to rupture and intraperitoneal hemorrhage. Rarely, adenomas become malignant (1).

Diagnosis is often suspected based on ultrasound or CT results, but biopsy is sometimes needed for confirmation. Gadoxetate-enhanced MRI, which allows functional imaging of the hepatobiliary system, is more sensitive than CT and can differentiate subtypes of adenomas at increased risk of progressing to malignancy (2). Recognition of the beta-catenin subtype is particularly important, because it has an approximately 10% risk of malignant transformation and should be resected (1).

Adenomas due to contraceptive use may regress if the contraceptive is stopped. If the adenoma does not regress, or if it is subcapsular, > 5 cm, or identified in a patient with male sex, surgical resection is often recommended (1).

This benign liver mass is the second most common solid liver lesion (1). Diagnosis is usually based on MRI or CT with hepatobiliary contrast; the classic appearance is a lesion with a central scar. But biopsy may be necessary for confirmation. Treatment is rarely needed unless symptomatic.

Hemangiomas are usually small and asymptomatic; they occur in up to 20% of adults and more frequently in women (1). Symptoms are more likely if they are > 4 cm; symptoms include discomfort, fullness, and, less often, anorexia, nausea, early satiety, and pain secondary to bleeding or thrombosis. These tumors often have a characteristic highly vascular appearance. Hemangiomas are found incidentally during ultrasound, CT, or MRI. CT typically shows a well-demarcated, hypodense mass; when contrast is used, there is early peripheral enhancement, followed by later centrifugal enhancement. Biopsy is usually not necessary, and treatment is usually not indicated. Resection can be considered if symptoms are troublesome or if a hemangioma is rapidly enlarging.

In infants, hemangiomas often regress spontaneously. However, large hepatic hemangiomas occasionally cause arteriovenous shunting sufficient to cause heart failure and sometimes consumption coagulopathy. Treatment may include beta blockers, systemic corticosteroids and other immunomodulatory therapy, medical treatment of heart failure when necessary, surgical removal, selective hepatic artery embolization, and, rarely, liver transplantation (2).

Lipomas (usually asymptomatic) and localized fibrous tumors (eg, fibromas) rarely occur in the liver.

Benign bile duct adenomas are rare, inconsequential, and usually detected incidentally. They are sometimes mistaken for metastatic cancer.