Post-infarction peripheral cysts of the lung in pediatric patients: a possible cause of idiopathic spontaneous pneumothorax.

Occlusion of the main pulmonary artery to the right lung in a newborn infant produced peripheral (subpleural) infarction of the lung and cyst formation. Two older infants were found at autopsy to have subpleural cysts of the upper lobes. One had had surgery for repair of an atrial septal defect and a patent ductus arteriosus eight months prior to death, while the second had died suddenly of carbon monoxide intoxication. The authors suggest that pulmonary arterial occlusion may have been responsible for cyst formation in all three cases and may produce cysts in other infants that lead to idiopathic spontaneous pneumothorax in older children and young adults. The presence of bronchopulmonary arteries in fetuses and newborn infants may provide the mechanism for the production of subpleural cysts following pulmonary arterial occlusion.