Department of Obstetrics and Gynecology, National Medical Center Hospital
Congenital cystic adenomatoid malformation of the lung, Antenatal diagnosis, Ultrasound
A case of type III congenital cystic adenomatoid malformation of the lung was diagnosed at 22nd week of gestation by ultrasound. Ultrasonogram showed a 38×24×28 mm cystic lesion in the fetal thorax. The cyst was surrounded by a large echogenic mass whose echo pattern resembled that of young placenta. The fetal heart was extremely displaced to the right side of the thorax. The diaphragm bulged downward to the abdominal cavity. Fetal ascites was observed but the maternal polyhydramnios was not present. Six days later, as the fetal ascites and the abdominal distension became severe, the pregnancy was decided to be terminated. The autopsy showed that the aborted baby was 818 grams in weight with 110 ml of ascites. The large, solid mass in the thorax turned out to be the lower lobe of the left lung, which was extremely hyperplastic and was histologically compatible with type III cystic adenomatoid malformation of the lung.