Pulmonary pseudocysts in the newborn infant.

Five neonates who developed a pulmonary pseudocyst are reported. All infants had clinical hyaline membrane disease and were treated with continuous distending airway pressure. The pseudocysts developed between 39 hours and 7 days of age. In all but one pulmonary interstitial emphysema preceded or occurred together with the development of the pseudocyst. All babies went on to complete clinical recovery without surgical intervention. Radiologic documentation of the spontaneous resolution of the pseudocyst was obtained in three infants and occurred over three days, five days, and three months, respectively.