Postpneumonectomy syndrome after left lung resection. A female infant with a right-sided aortic arch and ligamentum arteriosum underwent a left pneumonectomy for perinatal interstitial emphysema. Radiographic, bronchoscopic, and surgical evidence of compression of the right bronchial tree by the aorta, ligamentum arteriosum, right pulmonary artery, and thoracic spine subsequently developed. This report documents a rare example of postpneumonectomy syndrome following left lung resection. 