17.2Incidence (Except Benign Hepatic Tumors)

•One percent of all neoplasias in childhood

•Annually 1.4 in one million children less than the age of 16 years are newly diagnosed

•Ratio of males to females, 1.4–2.0:1.0

•Different incidences worldwide, for example, Far East more than Europe or the USA

•Relationship to hepatitis B in Taiwan: Due to systematic hepatitis B vaccination, the number of patients with hepatic carcinoma has been reduced

•Relationship to preterm birth rate: Inverse relationship between birth weight and frequency – 15 times higher risk in infants with birth weight less than 1,000 g

•High incidence in genetically associated syndromes: Beckwith–Wiedemann syndrome, familial adenomatous polyposis, trisomy 18, glycogen storage disease, hereditary tyrosinemia type 1, Alagille syndrome, Li-Fraumeni syndrome, ataxiatelangiectasia, tuberous sclerosis, Fanconi anemia

•Hepatoblastoma: Mostly in infants, rarely after the age of 3 years. Intrauterine development of hepatoblastoma possible

•Hepatocellular Carcinoma: Mostly in children older than 4 years of age; more common in adolescents. Histologically identical with carcinoma in adulthood

17.3Pathology and Genetics

17.3.1 Macroscopic Features

• Large, solid tumor mass; diameter less than 1 in. to more than 3 in

• Main occurrence in right hepatic lobe

• Minority with multinodular, bilateral spread (15–30%)

17.3.2 Microscopic Features

•Hepatoblastoma: Two patterns of differentiation:

–Epithelial type with embryonal or fetal features

–Mixed epithelial-mesenchymal type, partly with osteoid formation

–Some variants with variable embryonal differentiation

•Hepatocellular carcinoma: Histologically similar to hepatocellular carcinoma of adults

•Karyotype (hepatoblastoma):

–Commonly trisomy of chromosomes 2 and 20, rarely of chromosome 8, are associated

–Loss of heterozygosity (LOH) of chromosome 1p15 (as in other embryonal tumors, e.g., nephroblastoma or rhabdomyosarcoma)