Primary Fetal Lung Hypoplasia (PFLH): Imaging and Clinical Characteristics.

To describe in utero and postnatal imaging and clinical characteristics of primary fetal lung hypoplasia (PFLH).  A retrospective review of fetuses and neonates diagnosed in one academic tertiary center during an eleven-year period.  12 cases of PFLH were identified. 4 were bilateral and 8 had unilateral involvement. Prenatal sonographic characteristics, postnatal magnetic resonance imaging (MRI), computerized tomographic angiography (CTA), and histologic findings are described. 3 of the 4 bilateral cases were evaluated during fetal live. 2 were terminated and 2 died shortly after delivery. Among the 8 cases with unilateral PFLH, 7 involved the right lung and 1 the left lung. In fetuses with right hypoplasia, 5 showed characteristic features of Scimitar syndrome, while associated gastrointestinal tract (GIT) anomalies were presented in 2 cases. In this group 3 were born alive and the other 5 were terminated.  Primary PFLH is a rare anomaly that lethal in its bilateral form and with variable prognosis in its unilateral variant. Targeted evaluation of lung vascularity and exclusion of associated anomalies, especially of the GIT, are important prognostic factors.