Pulmonary alveolar proteinosis in the newborn.

A newborn presented with respiratory distress syndrome that was felt to be both clinically and roentgenographically typical of hyaline membrane disease. At autopsy, the lungs were firm, dry, and bulky, and sections from all lobes revealed mucin-negative, periodic acid-Schiff-positive, diastase-resistant material typical of pulmonary alveolar proteinosis. Electron microscopy documented the lamellar structure of the intra-alveolar material. There was no clinical or autopsy evidence of immunodeficiency.