A case of Fontan-related hepatocellular carcinoma successfully treated with proton beam therapy.

A 27-year-old woman was admitted to our hospital due to a liver tumor. She had been born late at 41 weeks of gestation and had heterotaxy syndrome, polysplenia, and complete transposition of the great arteries. She underwent percutaneous balloon angioplasty at 5 years of age and the Fontan procedure at 6 years of age. At 25 years of age, computed tomography detected liver congestion. Her alpha-fetoprotein level increased from 13 to 2098 ng/dL (L3 fraction 1.8%) at 27 years of age. Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging showed a 22-mm liver tumor in the second liver segment. The liver tumor was enhanced in the arterial phase and washed-out in the hepatobiliary phase; the patient was, therefore, diagnosed with hepatocellular carcinoma. Radiofrequency ablation and surgery were not indicated due to the proximity of the tumor to the inferior vena cava. Therefore, proton beam therapy was selected as conservative therapy, and a dose of 74 Gray equivalents in 37 fractions was administered at the University of Tsukuba Hospital. There were no severe adverse events and she survived for 38 months after treatment without recurrence.