Unusual features of pulmonary sling.

Patients with an anomalously placed left pulmonary artery ("pulmonary sling") typically have signs and symptoms of respiratory obstruction in the neonatal period. Experience with four previously unreported patients confirmed this. Typical radiographic features include unilateral air trapping (usually on the right side), an abnormal position of the esophagus, and a soft tissue mass interposed between the trachea and esophagus. Less common findings include a normal esophageal position, left-side air trapping, and delayed egress of neonatal pulmonary fluid. Both typical and atypical features were seen; the more unusual aspects are emphasized.