A FEMALE INFANT was born at 37.5 weeks' gestation, after an uneventful antenatal period and delivery. The Apgar scores were 6 and 8 at 1 and 5 minutes, respectively. Her birth weight was 3.3 kg. Thirty minutes after delivery she was noted to be tachypneic and hypothermic. Auscultation of her chest revealed decreased breath sounds on the right side. A chest radiograph was performed after transfer to the neonatal intensive care unit (Figure 1). An echocardiogram revealed a patent ductus arteriosus and a patent foramen ovale. A 4 × 4-cm cystic lesion was noted in the right hemithorax and extending posteriorly and inferiorly. A magnetic resonance imaging scan was performed on day 6 (Figure 2, Figure 3, and Figure 4).