Published on 22/03/2015 by admin
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Chapter 498 Neoplasms of the Liver
Cynthia E. Herzog
Hepatic tumors are rare in children. Primary tumors of the liver account for approximately 1% of malignancies in children, with an annual incidence of 1.6 cases per million children in the USA. Between 50-60% of hepatic tumors in children are malignant, with >65% of these malignancies being hepatoblastomas and most of the remainder, hepatocellular carcinomas. Rare hepatic malignancies include embryonal sarcoma, angiosarcoma, malignant germ cell tumor, rhabdomyosarcoma of the liver, and undifferentiated sarcoma. More common childhood malignancies such as neuroblastoma and lymphoma can metastasize to the liver. Benign liver tumors, which usually present in the first 6 mo of life, include hemangiomas, hamartomas, and hemangioendotheliomas.
Hepatoblastoma occurs predominantly in children <3 yr of age. The etiology is unknown. Hepatoblastomas are associated with familial adenomatous polyposis. Alterations in the antigen-presenting cell (APC)/β-catenin pathway have been found in most of the tumors evaluated. Hepatoblastoma also is associated with Beckwith-Wiedemann syndrome, which can show a similar loss of genomic imprinting of the insulin-like growth factor-2 gene. Low birthweight is associated with increased incidence of hepatoblastoma, with the risk increasing as birthweight decreases.
Hepatoblastoma can be epithelial type, containing fetal or embryonal malignant cells (either as a mixture or as pure elements), or the mixed type, containing mesenchymal and epithelial elements. Pure fetal histology predicts a more favorable outcome.
Hepatoblastoma usually presents as a large, asymptomatic abdominal mass. It arises from the right lobe 3 times more often than the left and usually is unifocal. As the disease progresses, weight loss, anorexia, vomiting, and abdominal pain may ensue. Metastatic spread of hepatoblastoma most commonly involves regional lymph nodes and the lungs.
A valuable serum tumor marker, α-fetoprotein (AFP), is used in the diagnosis and monitoring of hepatic tumors. AFP level is elevated in almost all hepatoblastomas. Bilirubin and liver enzymes usually are normal. Anemia is common, and thrombocytosis occurs in about 30% of patients. Hepatitis B and C serology should be obtained but usually are negative in hepatoblastoma.
Nelson Textbook of Pediatrics Expert Consult
