Spontaneous regression of pulmonary sequestration: prenatal and postnatal imaging findings.

Abstract

A 28-year-old woman at 24 weeks gestation was referred to our hospital for evaluation of a fetal lung mass. The differential diagnosis initially included pulmonary sequestration (PS) and microcystic congenital cystic adenomatoid malformation (CCAM), the latter because 2D color Doppler ultrasonography (US) showed no systemic artery feeding into the fetal lung lesion. At 25 weeks’ gestation, a complementary magnetic resonance imaging (MRI) scan showed a hyperintense left-sided triangular mass with a systemic feeding artery arising from the descending thoracic aorta (Fig. A, arrows), thereby indicating fetal PS. In a thick-slab T2-weighted image, the lesion showed hyperintensity in the left lower thorax (Fig. B, arrows). Follow-up MRI was performed 10 weeks later, and it showed partial regression of the sequestered lung with decreased, inhomogeneous signal intensity (Fig. C and D, arrows). Multidetector computed tomography (MDCT) angiography was arranged for preoperative evaluation on postnatal day 3, and it showed partial regression of the left lower lung PS as compared to prenatal MRI performed at 35 weeks’ gestation, a systemic feeding artery arising from the descending thoracic aorta (Fig. E and F, black arrows), and venous drainage into pulmonary veins (Fig. E and F, white arrows). The final diagnosis of PS was confirmed by surgery.