Hepatoblastoma is a primary malignant tumour of the liver and the most common primary liver tumour in children typically occurring in the first 2 years of life. ^{Reference Hiyama1,Reference Sharma, Subbarao and Saxena2} From 2002 to 2008, the incidence was 5.2 cases per million in children 1–4 years old. ^{Reference Howlader, Noone and Krapcho3} The aetiology of hepatoblastoma is unclear; however, one hypothesis is that the disease originates in utero. ^{Reference Linabery and Ross4} An association between hepatoblastoma and low birth weight (<2500 g) has been noted ^{Reference Maruyama, Ikeda and Koizumi5} with oxygen therapy and furosemide use as additional risk factors. ^{Reference Feusner and Plaschkes6} There have been no studies evaluating radiation exposure and hepatoblastoma risk. One study found that, of the seven patients diagnosed with hepatoblastoma between 2 and 4 years of age, two had cardiac disease: one with cardiomyopathy and one with Ebstein’s anomaly. ^{Reference Ansell, Mitchell, Roman, Simpson, Birch and Eden7} There have been no reports of hepatoblastoma in patients with single-ventricle congenital heart disease in contrast to hepatocellular carcinoma which is a recognised complication after Fontan completion. One multi-centre case series found the incidence of hepatocellular carcinoma was 1.3%. ^{Reference Egbe, Poterucha and Warnes8}

Case 1: A male infant with a diagnosis of an unbalanced right-dominant atrioventricular canal, double-outlet right ventricle with normally related great arteries, and severe pulmonic stenosis was diagnosed with hepatoblastoma at 19 months old. He was born at 38 weeks gestation weighing 2.56 kg. The pregnancy was complicated by type 2 diabetes mellitus, hypertension, and foetal growth restriction. He underwent a modified Blalock–Taussig shunt at five days old and bidirectional Glenn at 4 months old. His recovery after the bidirectional Glenn was complicated by pre-existing pulmonary disease, abdominal malrotation, and feeding intolerance requiring Ladd’s procedure and gastrojejunostomy tube placement. Prior to the diagnosis of hepatoblastoma, he had three cardiac catheterisations and 46 abdominal films.

He presented to the emergency room at 19 months old with two days of abdominal distension and fatigue. He was afebrile with sinus tachycardia and an oxygen saturation in the expected range of 75–85%. His exam was notable for a distended and firm abdomen. A computed tomography of the abdomen/pelvis demonstrated a large heterogeneous mass within the left lobe of the liver that was subsequently biopsied and identified as hepatoblastoma: PRETEXT stage IV – unresectable tumour without metastases. Initial alpha fetoprotein level was >303,000 ng/ml. He was determined not to be a liver transplant candidate because of cyanotic heart disease. He was treated with chemotherapy to reduce tumour size prior to resection. During cycle 2 of chemotherapy, he had a rise in alpha fetoprotein. Because of the tumour’s size and proximity to major blood vessels, tumour resection was thought not to be possible. The patient died shortly after this decision.

Case 2: A male infant with the cardiac diagnosis of hypoplastic left heart syndrome (HLHS) was diagnosed with hepatoblastoma at 16 months old. He was born at 37 weeks gestation following induction for foetal growth restriction. His birth weight was 2.82 kg. He underwent a Norwood procedure at five days of life. His inter-stage period was complicated by re-coarctation and hypoplastic pulmonary arteries that required branch pulmonary artery and aortic arch reconstruction and Sano shunt revision at 4 months old. Because of his hypoplastic pulmonary arteries, he was not a bidirectional Glenn candidate and therefore was listed for heart transplantation. He underwent heart transplant at 13 months old. Prior to the diagnosis of hepatoblastoma, he underwent 18 abdominal films, 2 abdominal computed tomographies, and 10 cardiac catheterisations. Roughly 3 months following heart transplantation, he was incidentally found to have a mass in the right posterior liver on an abdominal magnetic resonance imaging obtained for fever. Needle biopsy of the mass revealed hepatoblastoma PRETEXT stage I. Initial alpha fetoprotein was 8659 ng/ml. He underwent right hepatectomy with complete resection with negative margins. The month following resection, the alpha fetoprotein was 25,900 ng/ml. Due to his overall clinical status and clean margins, it was determined that chemotherapy was not indicated. There was no subsequent tumour growth prior to his death at 2 and a half years old following a bradycardic arrest of unclear aetiology.

Case 3: A female infant with the cardiac diagnosis of HLHS variant and partial anomalous pulmonary venous return was diagnosed with hepatoblastoma at 2 years old. She was born at 38 weeks gestation weighing 3.74 kg. The pregnancy was complicated by gestational diabetes. Genetic screening was notable for variant of unknown significance in A2ML1, which encodes alpha-2-macroglobulin-like 1, a protease inhibitor involved in Noonan syndrome. The patient underwent pulmonary artery banding and stenting of her atrial septum in the neonatal period and bidirectional Glenn and partial anomalous pulmonary vein repair at 6 months old. Prior to hepatoblastoma diagnosis, she underwent 15 abdominal films, 1 abdominal computed tomography, and 3 cardiac catheterisations.

She presented to the hospital at 2 years old following an episode of emesis, a 2-minute unresponsive episode, and desaturation to 50%. She was positive for respiratory syncytial and parainfluenza viruses. She was improving overall until hospital day three when she became fussy and complained of abdominal pain followed by non-bloody, non-bilious emesis preceding unresponsiveness and dusky appearance. Her physical exam was notable for a firm, distended abdomen. Laboratory evaluation demonstrated an acute drop in haemoglobin to 5.3 g/dl. An abdominal computed tomography was obtained demonstrating a large intra-hepatic mass with capsular disruption and resultant haemoperitoneum. She underwent embolisation of the left hepatic artery by interventional radiology and subsequent left hepatic resection.

The pathology confirmed the diagnosis of hepatoblastoma PRETEXT stage II. Her alpha fetoprotein at diagnosis was 159.8 ng/ml. She completed two cycles of chemotherapy. She remains off therapy without recurrence. She completed her Fontan circulation at 7 years old.