Fetus with prenatally diagnosed posterior mediastinal lymphangioma: characteristic ultrasound and magnetic resonance imaging findings.

Prenatal diagnosis of lymphangiomas located in the posterior mediastinum has been reported to be extremely rare. We present a fetus with a prenatally diagnosed posterior mediastinal lymphangioma found at 28 weeks' gestation. Fetal ultrasound and magnetic resonance imaging (MRI) revealed a 46 x 26 x 30 mm multicystic mass extending above the diaphragm, located in the posterior mediastinum. The mass was symmetrically shaped and surrounded the thoracic aorta. No remarkable change was noted in the size, shape and texture of the cyst by serial ultrasound and the fetus did not develop cardiac failure or hydrops in the antenatal period. Postnatal chest X-ray and MRI confirmed the prenatal findings. The infant was asymptomatic, so he was placed on close follow-up without any medical or surgical treatment.