Pediatric liver tumors account for 5-6% of abdominal masses in children. ¹ Hepatoblastoma (HB), although considered a rare pediatric disease, is the most frequent hepatic malignancy in children. Together with hepatocellular carcinoma, it accounts for almost 80% of primary malignant liver tumors in children and adolescents/young adults. ² Hepatoblastoma arises in infants and toddlers, while in teenagers. hepatocellular carcinoma is more frequent. ³ Most HB are sporadic, however, they may arise in the context of tumor predisposition syndromes, such as familial adenomatous polyposis (FAP), or in premature infants.  Recent genomic analysis of hepatoblastoma identifies distinct molecular and prognostic subgroups. ^4,5 Its incidence has been increasing worldwide, however, despite improvements in survival, disparities exist by age, tumor stage, and race or ethnicity. ^6-8  Hepatocellular carcinoma may arise in a previously healthy liver or in the context of a pre-existing metabolic or infective disease. ⁹ CTNNB1 exon 3 deletions and point mutations are characteristic of hepatoblastoma but may be also identified in a subset of hepatocellular carcinoma.  Other malignancies such as combined hepatocellular–cholangiocarcinoma, and cholangiocarcinoma are extremely rare in children. Among the benign epithelial neoplasms, hepatic adenomas are infrequent in children.
Among the benign mesenchymal neoplasms of liver, vascular tumors are the most frequent and include infantile hemangiomas and congenital hemangiomas, to be differentiated from vascular malformations. ^10,11 Mesenchymal hamartoma of liver is rare and occurs in infants, although rare cases are reported in older children. Among the malignant mesenchymal neoplasms, undifferentiated embryonal sarcoma of liver accounts for 2% to 15% of pediatric hepatic malignancies. ¹²