PICTORIAL ESSAY - IMAGING OF LIVER-TUMORS IN THE INFANT AND CHILD

Hepatosplenobiliary masses comprise approximately 5-6% of abdominal masses in the pediatric age-group. Hepatic tumors are classified into benign and malignant categories and then subclassified according to the cell of origin (mesenchymal versus epithelial). Solid benign tumors of epithelial origin include hemangioendothelioma, most commonly detected under the age of 6 months, and cavernous hemangioma, which is generally a tumor of adulthood. Mesenchymal hamartomas are rare, predominantly cystic tumors of developmental origin. Liver teratomas make up the rarest group of benign tumors. The majority of malignant primary tumors are of epithelial origin and include hepatoblastoma and hepatocellular carcinoma. Sarcomas are usually undifferentiated, but may rarely differentiate into angiosarcoma, mixed mesenchymal sarcoma, or rhabdomyosarcoma. Metastatic tumors to the liver are less common in the pediatric patient than in the adult. Common sources of metastatic disease to the liver in children include Wilms tumor, neuroblastoma, lymphoma, and leukemia [1,2]. Because surgery represents the mainstay of therapy in many of these lesions, detailed preoperative anatomic mapping is essential. Imaging evaluation of these masses has included a wide array of modalities, including ultrasound, radionuclide techniques, computed tomography (CT), and magnetic resonance imaging (MRI). MRI has shown the greatest promise in recent years because it combines the nonradiation advantage of ultrasound with the exquisite anatomic detail of CT. In addition, there is no dependence upon contrast delivery for visualization of vascular structures - a particularly important advantage in elucidating the potential resectability of liver masses. In the following we present the imaging spectrum of liver masses in infants and children, with emphasis on MRI.