Congenital alveolar capillary dysplasia: a developmental vascular anomaly causing persistent pulmonary hypertension of the newborn.

The clinical course and histologic findings are presented of an infant with an unusual form of pulmonary dysplasia. Characteristic sonographic findings and progressive hypoxemia led to the diagnosis of persistence of the fetal circulation. The patient expired despite ventilatory and pharmacologic intervention. Postmortem findings of severe pulmonary capillary hypoplasia, despite normal anatomical and biochemical parenchymal maturation, were observed. It is suggested that factors controlling pulmonary capillary maturation may be significantly different from those involved in airway and pulmonary parenchymal development.