Congenital lung malformations in the second trimester: prenatal ultrasound diagnosis and pathologic findings

To correlate prenatal sonographic diagnosis of cystic lung malformations with fetopathologic findings after termination of pregnancy.

We retrospectively analyzed the data of 16 terminated cases in which a cystic lung lesion was diagnosed pre- or postnatally.

On average, prenatal diagnosis was established on the 21(st) gestational week (range, 19-26 weeks). The cause of termination was severe polyhydramnios in 4 cases, nonimmune fetal hydrops in 4 cases, other congenital malformation in 5 cases (renal malformation, 2 cases; congenital diaphragmatic hernia, 3 cases), and obstetrical conditions (intrauterine death, placental abruption, spontaneous abortion) in 3 cases. In 11 cases, congenital cystic adenomatoid malformation (CCAM) was the presumptive prenatal diagnosis. Autopsy confirmed the prenatal diagnosis in 6 of them, while in the other 5 cases, an enteric cyst, a laryngeal atresia, an unidentified tumor, a pulmonary hypoplasia, and an extralobar pulmonary sequestration were found on histologic examination. On the other hand, the autopsy revealed CCAM in those 5 cases in which other malformations were suggested prenatally.

The prenatal sonographic diagnosis of CCAM is difficult. Our cases emphasize the important role of fetopathology even today in the verification of prenatal diagnosis based on sonographic examinations.