P180: Prenatal findings and differential diagnosis of Scimitar syndrome and pulmonary sequestration

Abstract

Scimitar syndrome and pulmonary sequestration have overlapping features. Pulmonary sequestration has been reported prenatally, but prospective antenatal diagnosis of Scimitar syndrome has not. We describe the antenatal ultrasound findings in these conditions that allowed the correct prenatal identification and their differentiation. Retrospective analysis of prenatal and postnatal data of Scimitar syndrome or pulmonary sequestration diagnosed prenatally since 1995. Right-sided ipsilateral mediastinal shift (relative to the affected lung) was the indication for referral in all three cases of Scimitar syndrome. The mediastinal shift was contralateral in all three cases of pulmonary sequestration. Lung echogenicity was focally increased in sequestration and normal in Scimitar syndrome. Hyperechogenic lung was the indication for referral in pulmonary sequestration, with two requiring prenatal insertion of a thoraco-amniotic shunt for significant pleural effusion. See table for summary of vascular anatomy findings. The differentiating ultrasound features between Scimitar syndrome and pulmonary sequestration are the laterality of mediastinal shift and the vascular anatomy. Pulmonary sequestration is easier to detect prenatally, due to the echogenic lung mass. Prenatal diagnosis of Scimitar syndrome is more challenging, due to normal lung echogenicity and the subtlety of vascular findings. Careful search for abnormal venous drainage in cases of isolated mediastinal shift should be undertaken if the diagnosis of Scimitar syndrome is to be made prenatally.