Abernethy malformation is an extremely rare congenital malformation characterised by an extrahepatic portosystemic shunt. Children with Abernathy malformation can develop hepatopulmonary syndrome (HPS) with pulmonary arteriovenous fistulas (PAVF) or pulmonary hypertension. | A 10-year-old boy with dyspnea and hypoxia: Abernathy malformation masquerading as pulmonary arteriovenous fistula