Excerpt from Cavernous Hemangioma, Liver

Synonyms, Key Words, and Related Terms: hepatic cavernous hemangioma, hepatic hemangioma, hemangioma of the liver, giant hemangioma of the liver, primary liver tumor, focal nodular hyperplasia, Kasabach-Merritt syndrome

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Background: Cavernous hemangioma is the most common primary liver tumor; its occurrence in the general population ranges from 0.4-20%, as reported in an autopsy series (Karhunen, 1986). Cavernous hemangioma arises from the endothelial cells that line the blood vessels and consists of multiple, large vascular channels lined by a single layer of endothelial cells and supported by collagenous walls. They are frequently asymptomatic and incidentally discovered at imaging, surgery, or autopsy.

Usually, they occur as solitary lesions. However, they may be multiple in as many as 50% of patients (Mergo, 1998). No lobar predilection exists. Hemangiomas typically measure less than 5 cm; some authors call those larger than 4-5 cm giant hemangiomas (Cappellani, 2000; Yang, 2001). They may be associated with focal nodular hyperplasia (Vilgrain, 2000). Hemangiomas are uncommon in cirrhotic livers; the fibrotic process in cirrhotic liver may prohibit their development (Dodd, 1999).

Pathophysiology: The natural history of liver hemangioma is not completely understood. Hemangiomas are probably congenital in origin. Hereditary factors may play a role in the pathogenesis of some familial forms. Although the growth of hemangiomas is reported in the literature, ectasia is believed to contribute to lesion enlargement (Nghiem, 1997). According to the findings of a recent study, hemangiomas become fibrotic and shrink in patients with progressive cirrhosis (Brancatelli, 2001).

The vast majority of hemangiomas (as many as 85%) are asymptomatic. Hemangiomas may cause symptoms because of the compression of adjacent structures, rupture, acute thrombosis, or consumptive coagulopathy (Kasabach-Merritt syndrome).

Sex: A distinct female preponderance was reported in surgical series, with a female-to-male ratio of 5:1 to 6:1. However, cavernous hemangioma of the liver affects both sexes equally in children and in autopsy series.

Age: Hemangiomas can occur in individuals of any age. They frequently occur in middle-aged women.

Clinical Details: Pressure on the stomach and duodenum caused by large pedunculated lesions may cause vague abdominal pain, early satiety, nausea, and vomiting. Pedunculated hemangiomas may twist and cause acute abdominal pain (Tran-Minh, 1991). Compression of the inferior vena cava may result in Budd-Chiari syndrome (Hanazaki, 2001). Acute thrombosis may result in acute inflammatory changes that cause fever, abdominal pain, and abnormal liver function (Pol, 1998). Spontaneous or posttraumatic rupture is a catastrophic complication that occurs in about 1-4% of hemangiomas; it has a considerable mortality rate, as high as 60% (Cappellani, 2000).

Preferred Examination: Most patients with liver hemangioma are asymptomatic. Clinical findings usually do not contribute to the diagnosis. Laboratory test results may suggest anemia, and reduced hematocrit levels may be present in patients with ruptured hemangiomas. In patients with giant hemangiomas associated with Kasabach-Merritt syndrome, bleeding and clotting parameters may be abnormal.

Most hemangiomas are incidentally detected at imaging studies. Ultrasonography is a cost-effective imaging modality for diagnosis of a hemangioma. However, CT and/or MRI may be required to specifically diagnose hemangioma.

Limitations of Techniques: Ultrasonography is a heavily operator-dependent technique; its performance depends on the expertise and experience of the sonographer. In addition, the acquisition of satisfactory images in obese patients is technically difficult. Contrast-enhanced CT is relatively contraindicated in patients with renal insufficiency and in those with a prior history of hypersensitivity to iodinated contrast agents. MRI may be the preferred modality of choice in the characterization of hemangiomas .....