Fetal echogenic lung lesions: prenatal ultrasound diagnosis and outcome

The differential diagnosis of echogenic areas in the fetal chest include congenital diaphragmatic hernia (CDH), cystic adenomatoid malformation (CAM), sequestrated lung and tracheal or bronchial atresia. The purpose of this study was to evaluate the accuracy of prenatal diagnosis and document outcome in fetuses with echogenic chest lesions. Seventeen fetuses with echogenic chest masses were seen in our unit between 17 and 36 weeks' gestation over a 5-year period. We reviewed these cases retrospectively for prenatal diagnosis, postnatal diagnosis and outcome. Prenatal diagnosis was correct in 13 fetuses, with CDH in 8, sequestrated lung in 4 and tracheal atresia in 1. Four fetuses had incorrect or uncertain prenatal diagnoses. In three fetuses CDH and CAM could not be differentiated. After delivery two of these had CDH and one had sequestrated lung. One fetus with bilateral lesions had prenatal diagnosis of bilateral CAM. Post-mortem examination revealed tracheal atresia as part of Fraser syndrome. All five babies with sequestrated lung are well and none required surgery. Ten fetuses had CDH, two pregnancies were terminated, one died in utero, five died as neonates and two babies survived following surgery. The study reveals that in a minority of fetuses CDH and CAM could not be differentiated prenatally. We agree with recent reports of fetal sequestrated lung describing sonographic improvement in utero. A large lesion on initial scan does not necessarily predict a poor neonatal outcome in this condition. This, together with the poor outcome in fetuses with echogenic CDH and tracheal atresia, has important implications for prenatal counselling.