Surveillance imaging detects hepatocellular adenomas and carcinomas in individuals with Fontan circulation.

[PURPOSE] To describe institutional surveillance practices for hepatic neoplasms in people with Fontan circulation and report the number and types of biopsied lesions identified.

[METHODS] We retrospectively analyzed surveillance liver imaging, serum alpha-fetoprotein (AFP), and histopathology in individuals with Fontan circulation cared for at our hospital between 2013 and 2022. Clinical information and subsequent management were reviewed. Imaging for hepatocellular adenomas (HCAs) and malignant lesions was assessed for key diagnostic features.

[RESULTS] A total of 1110 liver imaging studies were performed in 686 individuals. Twenty-eight focal liver lesions (in 23 patients) were biopsied: 10 focal nodular hyperplasia-like lesions, seven HCA, seven hepatocellular carcinomas (HCCs), one cholangiocarcinoma, one hamartoma, one posttransplant lymphoproliferative disorder lesion, and one hemangioma. Two HCAs demonstrated malignant transformation to HCC. Median ages at diagnosis were 17.5 years for HCA and 26.6 years for malignant tumors. Most HCAs (5/7) and HCCs (5/7) were initially detected with MRI. Only three of seven patients with HCC had elevated AFP prebiopsy. Imaging features - including arterial phase hyperenhancement, washout, fat content, and hepatobiliary phase hypointensity - substantially overlapped between HCAs and HCCs. Among patients with malignant neoplasms ( n  = 8), four died, three underwent percutaneous therapy followed by heart-liver transplantation, and one underwent ablation alone.

[CONCLUSION] Surveillance imaging in this cohort of children and adults with Fontan circulation identified hepatocellular neoplasms in patients as young as 15 years old. MRI detected most lesions, AFP was often normal in HCC, and substantial imaging overlap between HCAs and HCCs reinforces the need for multidisciplinary review to guide diagnosis and management.