A 20-month-old male child died during an episode of acute bronchitis. The autopsy revealed massive hypertrophy and acute dilatation of the right heart which was caused by pulmonary hypertension exhibiting plexogenic arteriopathy and necrotizing arteriitis of small lung vessels. Further examination revealed complete old fibrotic occlusion of the extrahepatic portal vein and a large porto-systemic shunt. Esophageal varices indicating portal hypertension were not present. Histology showed enlarged hepatic arteries within the portal tracts while branches of the portal vein were lacking. The placenta had been examined at the time of birth and multiple chorangiomas reported. Furthermore, multiple old and florid occlusions of fetal vessels had been detected together with focal lymphoplasmocytic inflammation, which may indicate that intrauterine infection and vascular compromise were the cause of the complete closure of the portal vein around birth. The association of pulmonary hypertension with liver disease is well known, and portal hypertension has been considered a key factor in the pathogenesis of pulmonary hypertension. However, this case illustrates that portal hypertension is not a requisite for the development of pulmonary hypertension. It rather suggests that plexogenic arteriopathy of the lungs can be caused by porto-caval shunting independent of liver damage and portal hypertension. Toxic metabolites of nutrients or residual activity of pancreatic enzymes reaching the pulmonary vascular bed may be involved in the pathogenesis.