Hepatoblastoma (HB) is a malignant hepatic tumor and is the most common pediatric liver cancer. It is characterized by anorexia, weight loss and an enlarged abdomen. HB is more common in patients with familial adenomatous polyposis (FAP), and can occur in patients with other pre-existing liver conditions. About 5% of HB cases are associated with genetic factors, especially overgrowth syndromes, such as Beckwith-Wiedemann syndrome (BWS) or hemihypertrophy. The disease is hepatoblastoma (MONDO_0018666, a Monarch Disease Ontology term). Also known as: HBL, hepatoblastoma, malignant, paediatric embryonal hepatoma, paediatric hepatoblastoma, pediatric embryonal hepatoma, pediatric hepatoblastoma.