Early prenatal diagnosis of type II cystic adenomatoid malformation of the lung: sonographic and histological findings

Abstract

Cystic adenomatoid malformation is a rare abnormality of the fetal lung. Depending on the size and histology of the cyst, it is classified as type I, II or III. With improving ultrasound technology, prenatal diagnosis during the mid-trimester is now possible; however, the earliest previous reports of type II cases have been at 23-24 weeks' gestation. We here report cases diagnosed at 19.5 and 20.5 weeks. In contrast to the appearance of multiple small cysts seen later in pregnancy, these cases showed a predominance of marked hyperechogenicity, usually associated with type III malformations, with small areas of lung involved by sonographically detectable cysts. Both families chose pregnancy termination. Sonographic findings, counselling, and histology are presented and discussed.