Liver Tumors

Abstract

Liver “masses” are not uncommon and are linked with a wide assortment of conditions. Infections and fatty deposits can mimic a tumor. Other conditions, such as choledochal cysts and vascular malformations, will also present as liver “masses.” In this chapter, we will confine our discussion to malignant liver tumors. Liver tumors account for about 1% of all pediatric cancers or approximately 2.4 cases/100,000. Each year in the USA, approximately 125–150 new cases of liver cancer are diagnosed in children. Hepatoblastoma is the most frequent malignant liver tumor in children and represents approximately two thirds of all pediatric liver cancers. Hepatoblastoma usually arises in the first few years of life, with a mean age of onset of approximately 16–20 months, and almost all cases occur before 4 years of age. The incidence of hepatoblastoma has been increasing over the last several decades. Hepatoblastoma tumor cells resemble cells seen in the developing liver, and, therefore, this tumor is categorized as an embryonal tumor. Hepatocellular carcinoma (HCC) is the main liver tumor manifesting in the second decade of life. Both hepatoblastoma and HCC seem to arise more commonly in boys than in girls. Other pathologically distinct liver tumors are less frequently diagnosed in children and include undifferentiated embryonal sarcoma, rhabdoid tumor, rhabdomyosarcoma, germ cell tumors, lymphoma, leiomyosarcoma, and angiosarcoma. Metastatic disease from neuroblastoma, Langerhans cell histiocytosis, Wilms’ tumor, lymphoma, and leukemia can also commonly cause liver lesions and should be included in the differential diagnosis. Benign neoplasms account for approximately one third of all pediatric liver lesions and include vascular tumors (hemangiomas and hemangioendotheliomas), mesenchymal hamartomas, focal nodular hyperplasia, and adenomas.