Benign to Malignant Hepatic Lesion Transformation in Abernethy Malformation

Abernethy malformation or congenital extrahepatic portosystemic shunt is an extremely rare condition whereby the portomesenteric blood drains into a systemic vein and bypasses the liver through a complete or partial shunt. Severe complications include hyperammonemia and encephalopathy, benign and malignant liver tumors, and hepatopulmonary syndrome. We describe a case where a female adult diagnosed with congenital extrahepatic portosystemic shunt subsequently developed focal nodular hyperplasia and then hepatocellular carcinoma.