Prenatal sonographic characteristics and Doppler blood flow study in a case of a large fetal mediastinal teratoma

Although fetal mediastinal teratomas may result in respiratory distress in the neonatal period and lead to perinatal mortality, they are rarely diagnosed prenatally. Furthermore, their impact on fetal hemodynamics has never been described. We report a case of a large fetal mediastinal teratoma prenatally visualized at 38 weeks' gestation by both two- and three-dimensional ultrasound. We also describe the associated changes in the Doppler flow velocimetry, namely, a decrease in cardiac output, prolonged acceleration time in the pulmonary artery and an increase in the umbilical artery S/D ratio. The baby was well at the 5-month follow-up after an operation in the neonatal period. From our case, we believe that accurate prenatal diagnosis and assessment by two- and three-dimensional ultrasound as well as Doppler flow velocimetry may contribute to a better perinatal outcome.