Congenital cystic adenomatoid malformation in the fetus: natural history and predictors of outcome.

Cystic adenomatoid malformation (CCAM) is a rare lesion that often is diagnosed by prenatal ultrasonography. Outcome varies from hydrops and fetal death to resolution before birth. The authors reviewed their 7-year experience with 17 fetuses diagnosed with CCAM by prenatal ultrasonography to determine the natural history of the lesion and to identify factors that might predict outcome. Of the 17 fetuses, five died during intrauterine life (3 terminations, 2 fetal deaths); four of them had hydrops. Twelve fetuses were carried to term. Only one had prenatal intervention: a thoracoamniotic shunt at 24 weeks. All 12 infants survived and underwent resection. Only four required neonatal support (1 extracorporeal membrane oxygenation, 2 ventilator, 1 oxygen). The initial CCAM:chest ratio, degree of mediastinal shift at time of diagnosis, location of CCAM, and age at time of diagnosis did not correlate with outcome. Sonographically predicted pathological type did not correlate with pathological diagnosis after surgery, or with outcome. The only accurate predictors of outcome were presence of hydrops (all died) and decrease in size of CCAM during gestation (all survived). The outcome for fetuses with CCAM may be better than previously recognized. Many of the lesions decrease in size, despite significant mediastinal shift and lung compression at the time of diagnosis. Fetal intervention should be considered only for fetuses with hydrops. Others should be monitored with serial ultrasonography. Parental counseling, especially regarding pregnancy termination, should reflect the positive outcome noted in most cases.