Prenatal diagnosis of cystic adenomatoid malformation of the lung.

Cystic adenomatoid malformation of the lung (CAM) is an uncommon malformation in which normal tissue is replaced by cysts of various sizes. This malformation may be diagnosed prenatally with ultrasound by visualization of cystic masses in the fetal chest, which may occur in association with fetal hydrops. Three cases of fetal hydrops secondary to cystic adenomatoid malformation of the lung are described; in one case cystic lesions in the chest were clearly demonstrated.