[Congenital cystic adenomatoid malformation detected by prenatal sonography; report of 2 cases].

We report 2 cases of congenital cystic adenomatoid malformation (CCAM) detected by prenatal sonography. The first CCAM was diagnosed by fetal sonography in a female fetus at 30 weeks' gestation. The infant was born at 37 weeks' gestation, with a body weight of 2,770 g. After birth, chest computed tomography (CT) showed a multicystic mass in the middle lobe of the lung. She remained asymptomatic until age 21 months, when she suffered pneumonia. Two months later, middle lobectomy was performed. The second CCAM was diagnosed by fetal sonography in a female fetus at 25 weeks' gestation. She was born at 39 weeks' gestation, with a body weight of 3,292 g. Four days after birth, CCAM type II was diagnosed by chest CT. The infant was asymptomatic, and left lower lobectomy was performed 11 months after birth.