Aims: To describe a third case of congenital pulmonary acinar dysplasia, comparing its clinicopathological features with those of the two previous cases and with cystic adenomatoid malformations.
Methods and results: An externally normal female infant was born to a 25-year-old after a normal pregnancy. Ventilation was not established. At autopsy the hypoplastic lungs showed bronchial development but no acinar development, resembling the pseudoglandular phase of 16 weeks gestation. As in the previous cases the infant was female, born at term with unaffected older sibling(s): however, no intrapulmonary haematopoietic tissue was identified in the present case. Cystic adenomatoid malformations also resemble microscopically the pseudoglandular phase but are focal pulmonary hyperplasias rather than generalized pulmonary hypoplasias.
Conclusion: Congenital acinar dysplasia is a rare, apparently sporadic lethal developmental defect resulting in pulmonary hypoplasia due to failure of lung development beyond the pseudoglandular phase seen at 16 weeks gestation.