Hepatoblastoma is the most common primary liver tumour in children; however, there are no reported incidences in the single-ventricle congenital heart disease population. We present three cases in patients with single-ventricle heart disease with a mean age at diagnosis of 19.7 (±4) months. The diagnosis was made prior to Fontan completion in all three cases. These represent the only documented hepatoblastoma cases in single-ventricle patients.

Hepatoblastoma is the most common malignant liver tumour in early childhood. The metastatic extension of hepatoblastoma into the left atrium via the pulmonary vein is rare. Reported lesions almost always involve a right-sided approach. Here we report the case of a 3-year-old girl with a recurrent hepatoblastoma at multiple sites, including the left atrium, brain, and lung. The patient was treated surgically for the prevention of further embolic complications and cardiac failure.

We report on a 3-year-old girl, from a 3-generation family with an FGFR3 Pro250Arg mutation, who in addition to craniosynostosis, had a laterality disorder and hepatoblastoma, following a pregnancy complicated by maternal insulin-dependent diabetes. The clinical features possibly result from the combined effects of the maternal diabetes and the familial FGFR3 mutation, thus representing a unique gene–environment interaction that may have implications for the understanding of the phenotypes described in this child.