Abstract
A 28-year-old woman at 32 weeks of gestation was referred to us for evaluation of a fetal mediastinal cystic mass detected during prenatal ultrasonography. MRI revealed a fluid-filled tubular structure extending from the carina along the presumed course of the fetal esophagus (Fig. A and B, arrows), polyhydramnios, and right pleural effusion (Fig. B, arrowhead). The diagnosis of esophageal duplication cyst was confirmed at the operation carried out after delivery.