Vanishing fetal lung malformations: Prenatal sonographic characteristics and postnatal outcomes

Background/purpose: The purpose of this study was to examine the natural history and outcomes of prenatally diagnosed lung masses that appear to undergo complete regression before birth. Methods: An IRB-approved retrospective review was performed on 100 consecutive fetuses with a congenital lung malformation at a single fetal center. Prenatal and postnatal imaging as well as outcomes of vanishing fetal masses was analyzed and compared to those with persistent fetal masses. Results: Seventeen lesions (17%) became sonographically undetectable at 35.3 +/- 2.3 weeks gestation. Vanishing fetal masses were associated with microcystic disease (100% vs. 69%, p = 0.005) and a low initial congenital pulmonary airway malformation volume ratio (CVR; 0.31 +/- 0.35 vs. 0.70 +/- 0.66, p = 0.002) when compared to thosewith persistent fetal lesions. Based on postnatal CT imaging and pathology data, 10.3% of all fetal masses completely regressed. The positive predictive value and negative predictive value of prenatal ultrasound for detecting lung malformations in late gestation were 96% and 43%, respectively. All infants with vanishing fetal lesions were asymptomatic at birth and were more likely to be managed nonoperatively (75% vs. 22%, p < 0.0001) when compared to infants with persistent fetal masses. Conclusions: Vanishing lung lesions late in gestation are relatively common and are associated with a low CVR and microcystic disease. (C) 2015 Elsevier Inc. All rights reserved.