Infantile hemangioendothelioma is a benign tumor of the liver composed of anastomosing vascular channels lined by plump endothelial cells. At initial presentation, most patients are 6 months of age or younger and have hepatomegaly or an abdominal mass. Congestive heart failure, bleeding, anemia, jaundice, and cutaneous or visceral hemangiomas may also be present. Grossly, the lesions are usually well circumscribed and may be focal, multifocal, or diffuse. Large solitary lesions are often associated with central hemorrhage or necrosis. Radiography reveals a mass that is occasionally calcified. Angiography reveals hypervascular lesions, often with arteriovenous shunting. A solid lesion with variable echotexture is noted at ultrasound. Computed tomography typically shows a low-attenuation solid lesion with peripheral enhancement. Central enhancement is often lacking except in smaller lesions. At magnetic resonance imaging performed with T2-weighted pulse sequences, the lesions usually have high signal intensity. Spontaneous regression of the tumor occurs, although patients may die of associated conditions.