Imaging description

An infant who was several weeks old presented with an incidental finding of a palpable abdominal mass on a routine clinical examination. The child did not have fever or any other clinical abnormalities. The liver was palpable 10 cm below the right costal margin. Ultrasound and CT studies demonstrated a large, multiseptated cystic lesion in the right lobe of the liver (Fig. 48.1). This was thought to be most consistent with a mesenchymal cystic hamartoma of the liver.

Importance

Mesenchymal hamartoma is a rare, benign liver neoplasm, typically found in children less than two years of age. The lesion is slightly more common in boys than in girls. It is a developmental cystic liver tumor, composed of proliferations of variably myxomatous mesenchyme and malformed bile ducts. Treatment consists of surgical resection.

Typical clinical scenario

Patients typically present with an asymptomatic abdominal mass. Rarely, complications including ascites, jaundice, and even congestive heart failure can occur. Since mesenchymal hamartomas are congenital malformations, they may be detected prenatally. The size is highly variable. The lesions may grow rapidly in the postnatal period, followed by growth stasis or even some regression. Most lesions are located within the liver parenchyma, although rare cases of pedunculated lesions have been described as well.