Acinar dysplasia: a new form of pulmonary maldevelopment.

A term neonate died of unrelenting respiratory distress several hours after birth. Autopsy of the normal-appearing infant revealed slightly small lungs with increased lobular markings, a right aortic arch, and bilateral thinned renal cortices. In contrast to most forms of pulmonary hypoplasia, the term neonate had deranged air spaces lined by ciliated bronchial epithelium, without development of alveoli, and with increased amounts of intervening fibrous tissue. It is proposed that an alteration in the epithelial-mesenchymal interactions during development accounted for both the unique pulmonary maldevelopment and the renal abnormalities.