CT Scan of Pediatric Liver Tumors

Hepatic masses constitute only 5% to 6% of all intra-abdominal masses in children (Pobeil & Bisset, 1995) and primary hepatic neoplasms constitute only 0.5% to 2% of all pediatric malignancies (Davey & Cohen, 1996). Primary hepatic neoplasms are the third most common abdominal malignancy in childhood, after Wilms’ tumor and neuroblastoma (Davey & Cohen, 1996). The majority of liver tumors in children are malignant. Only about one third of the liver tumors are benign (Jha et al., 2009). Most children with benign or malignant liver masses present with a palpable mass on physical examination. Other presenting symptoms include pain, anorexia, jaundice, paraneoplastic syndromes, hemorrhage, or congestive heart failure. Although it is often obvious that these children have an upper abdominal mass, the organ of origin is often not clear without imaging. Pediatricians and surgeons began to order more imaging studies because advances in imaging technology improved the diagnosis and management of disease. Imaging of pediatric hepatic masses has included multiple modalities, such as ultrasound, CT scan, MR imaging, angiography, and radionuclide techniques. Because surgical resection remains the mainstay of treatment for many of these lesions, detailed depiction of the extent of the mass and relationship to hepatic anatomy is essential. Ultrasound is usually the initial imaging modality in the evaluation of a child with a suspected abdominal mass. Ultrasound accurately excludes a mass when it is not present and identifies the organ of origin when a mass is present. Identifying the organ of origin helps determine the remainder of the child's imaging work-up. Ultrasound also evaluates whether a mass is cystic or solid and assesses vascular flow. When ultrasound confirms the lesion is in the liver, usually additional imaging is obtained with CT scan or MR imaging. The advantage of CT requires less or no anesthesia due to faster scan times. So CT has always played a major role in the imaging of the liver. But at the same time pediatric patients present unique technical challenges for CT. Children are not simply small adults, and CT scan principles drawn from experience with adults can not accurately be extrapolated to the pediatric population. The methods of CT examination should be adjusted. Whether CT scan or MR imaging is the modality of choice for definitive imaging of liver masses is a controversial issue. The choice is usually based on institutional experience and modality availability. Nevertheless, the development of multidetector row CT (MDCT)