METHODS
This is a retrospective study of all consecutive patients diagnosed prenatally with hyperechoic lung images examined at our institution between 2009 and 2018. The study was approved by the institutional review board and no written consent was required from the families.
Information on pre- and post-natal periods and imaging were retrieved from the medical charts. Prenatal evaluation was performed by a fetal medicine specialist and monthly serial ultrasound examination was performed from referral and up until delivery using a Voluson 730, Expert E8 or E10 (General Electric, Zipf, Austria). Each ultrasound examination included description of the mass and its evolution since the last exam: laterality, echogenicity, detection or absence of a feeding systemic arterial supply, and size in the three plans. Fetal hemodynamics was also serially assessed. Presence or absence of complications defined as mediastinal shift, compression of neighboring organs, signs of heart failure, polyhydramnios and hydrops were evaluated.
Gestational age at birth and birth weight were recorded; neonatal and postnatal respiratory signs and symptoms were assessed in all cases. The correlation between prenatal ultrasound features and neonatal symptoms was examined. Postnatal management included confirmation of the prenatal findings by chest x-ray in the first days of life and thoracic CT-scan without contrast injection or MRI within the first 6 months of birth.
The need for surgery was assessed by a pediatric surgeon based both on clinical symptoms and CT-scan features. When surgery was required, the histology of the malformation was studied. When conservative management was decided, imaging follow-up was based on CT-scan with low radiation dose. Patients with macrocystic malformation (BC, PCM or hybrid masses) were always referred for surgery, even when asymptomatic. This decision was taken considering the risk of over infection of the cysts, the surgical difficulties after infectious complications and the potential for malignancy. Patients with CLE were operated only when showing respiratory symptoms or signs of compression on follow-up CT-scan. In case of BPS, the surgical indication was based on the presence of secondary clinical symptoms, increase in size of the lesion on follow-up imaging or large systemic arteries.