Lung structure in asphyxiating thoracic dystrophy.

It has been assumed that asphyxiating thoracic dystrophy (ATD) is always associated with abnormal lung development due to the small thoracic cage. Applying precise quantitative morphometric techniques to the injected and inflated lung from an infant with ATD who died at 4 months of age, normal lung growth was demonstrated. The number of bronchial generations and preacinar arteries was normal, indicating normal development in the first 16 weeks of intrauterine life. Alveolar number and acinar complexity suggested that alveolar growth was normal at birth and had continued with only minor impairment after birth. Arterial changes compatible with hypoxic pulmonary hypertension were also present.