Outcome of the Prenatally Diagnosed Congenital Cystic Adenomatoid Lung Malformation: A Canadian Experience

Congenital cystic adenomatoid malformation of the lung (CCAM) is diagnosed by prenatal ultrasonography with an increasing frequency but controversy persists as to its prognosis and prenatal management. METHOD: A multi-institutional study of cases of CCAM diagnosed antenatally identified by ultrasonographers and by a review of hospital charts. RESULTS: We obtained 48 cases from five centers. We estimate the incidence of CCAM at 1:25,000 to 1:35,000 pregnancies. The incidence of voluntary abortions was 15% (7/48), of spontaneous abortions 2% (1/41) and of postnatal death 10% (4/40). One of the postnatal deaths was from trisomy 18. Of the 7 aborted fetuses, 2 had multiple malformations and 1 had severe hydrops and oligohydramnios; the other 4 had a large mass with mediastinal displacement but without hydrops. When pregnancy was allowed to continue, 56% of the lesions regressed spontaneously, even though one third of these had initial progression. In 17 cases (42%) the mediastinal shift corrected itself, sometimes by simple growth of the fetus but most often by a decrease in the size of the lung mass. In 1 fetus, repeated needle decompressions followed by double-pigtail catheter drainage of large cysts allowed regression of hydrops. Despite this, neonatal death occurred from pulmonary hypoplasia. CONCLUSION: CCAM can lead to fetal or neonatal demise from hydrops, lung hypoplasia, prematurity or severe associated malformations, but has a good prognosis in the majority of cases.