Pulmonary epithelial cell maturation in hyperplastic lungs associated with fetal tracheal agenesis

Background/Purpose: Cellular differentiation of pulmonary hyperplasia has not been reported in human cases. The authors studied surfactant protein expression and ultrastructure of pulmonary epithelial cells in fetal hyperplastic lungs associated with congenital tracheal agenesis. Methods: The maturation of pulmonary epithelial cells was assessed by immunohistochemical examination for surfactant proteins (SP-A, mature SP-B, proSP-B, proSP-C, and SP-D) and transmission electron microscopy. As controls normal lung portions of 8 fetuses born at 21 weeks gestation were used. Results: Mature SP-B and SP-D was detected in terminal airways in this case, but not in controls. In electron microscopy, lamellar bodies were recognized, and glycogen granules were less abundant in terminal airway cells. Conclusion: The differentiation of pulmonary epithelial cells appeared to be more advanced for the gestational age in pulmonary hyperplasia with congenital tracheal agenesis.