Metachronous hepatocellular carcinoma in a patient with Fontan physiology and type I congenital absence of the portal vein: repeat hepatectomy in the setting of dual abnormal hepatic hemodynamics: a case report

Fontan-associated liver disease is a recognized long-term consequence of the Fontan circulation and may progress to cirrhosis and hepatocellular carcinoma (HCC). Congenital absence of the portal vein (CAPV) is another rare vascular abnormality associated with hepatocellular nodules and hepatocellular neoplasia. The coexistence of these two conditions may create a unique carcinogenic and hemodynamic environment, but its surgical implications remain undefined. Recent molecular studies have further suggested that Fontan-associated HCC may be characterized by DNA damage-related genomic features. We report a 29-year-old man with Fontan physiology and type I CAPV who developed metachronous HCC and underwent two curative hepatectomies. The first HCC arose 21 years after Fontan completion in the setting of multiple focal nodular hyperplasia-like nodules, cirrhosis, and type I CAPV. Because conventional inflow control was deemed inappropriate and aggressive low-central venous pressure (CVP) management was physiologically constrained, the first hepatectomy was preceded by transarterial embolization and performed with intermittent hepatic arterial clamping and head-up positioning. CVP decreased from 20 to 15 mmHg during transection. Six years later, a second HCC developed in segment 2 and was treated by repeat partial hepatectomy. During the second operation, arterial clamping was not feasible because of dense hilar adhesions, and parenchymal transection was performed under head-up positioning alone, with CVP remaining around 16 mmHg. Pathological examination showed moderately differentiated and well-differentiated HCC, respectively, on a background of F4 cirrhosis with chronic hemodynamic liver injury. Additional immunohistochemical evaluation showed scarce γH2AX expression in the HCC tissue, whereas γH2AX expression was diffusely increased in the adjacent non-tumorous cirrhotic liver, suggesting widespread DNA damage signaling in the background liver. HCC arising in the setting of Fontan physiology and type I CAPV should be understood not simply as a rare coincidence, but as a condition shaped by dual abnormal hepatic hemodynamics. These features may influence carcinogenesis, portal hypertensive manifestations, and the feasibility of hepatectomy. Careful anatomical and physiological assessment is therefore essential for treatment planning, and sustained long-term surveillance is warranted given the persistent risk of recurrence.