Management of fetal lung lesions

We have learned from prenatal diagnosis that there is a wide spectrum of clinical severity for fetuses that have a lung mass. Accurate prognostic information is necessary for providing appropriate management and parental counseling. If an associated life-threatening anomaly is present or if the mother is ill with the mirror syndrome, then the family might choose to terminate the pregnancy. If the fetus is not hydropic and an isolated fetal lung lesion is present, the mother is followed by serial ultrasound and arrangements are made for the best possible care after birth. Some CCAMs and many BPSs will shrink in size, so it is important to try to differentiate these lesions using prenatal diagnostic criteria, although this technique is not always possible. All fetuses that had fetal thoracic masses without hydrops in our series survived in the setting of maternal transport, planned delivery, and postnatal evaluation at a facility with ECMO capability. Many of the babies that had large lesions at our center required ventilatory support, and six babies needed treatment with ECMO. Our impression is that these nonhydropic fetuses that had lung masses had less lung hypoplasia and a much better prognosis than those that had diaphragmatic hernia despite a similar degree of mediastinal shift as judged by prenatal sonography. In asymptomatic neonates that have a cystic lung lesion, we believe that elective resection is warranted because of the risks of infection and occult malignant transformation. Malignancies consist mainly of pleuropulmonary blastoma in infants and young children and bronchioloalveolar carcinoma in older children and adults. After confirmation of CCAM location by postnatal chest CT scan with intravenous contrast, we recommend elective resection at 1 month of age or older. This age has been chosen because anesthetic risk in babies decreases after 4 weeks of age. An experienced pediatric surgeon can safely perform a lobectomy in infants with minimal morbidity. Early resection also maximizes compensatory lung growth. In contrast, we have usually followed patients with a tiny, asymptomatic, noncystic BPS if we are confident of the diagnosis based on postnatal imaging studies. We do not favor the approach of catheterization and embolization for the treatment of larger BPS lesions. If the fetus is hydropic at presentation or if hydrops develops during serial follow-up, management depends upon the gestational age. For hydropic fetuses of greater than 32 weeks' gestation, early delivery should be considered so that the lesion can be resected ex utero, but the neonatal outcome is dismal. We recently managed two such cases using an ex utero intrapartum therapy (EXIT) strategy with resection of the mass during the EXIT procedure. Both fetuses survived and one required the use of ECMO. For hydropic fetuses of less than 32 weeks' gestation, there is now a new therapeutic option, treating the lesion before birth.