Mediastinal teratoma as a rare cause of hydrops fetalis and death: report of 3 cases.

Background: Congenital mediastinal teratomas are rare and may present with nonimmune hydrops. The lesion may be misinterpreted on ultrasound.

Cases: A 21-year-old woman, gravida 2, para 0111, was evaluated at 19 4/7 weeks of gestation for suspected fetal death. An ultrasonogram confirmed the death and revealed a posterior encephalocele and possible herniated liver in the chest. At autopsy a 5.2 x 7.5 x 1.0-cm mediastinal teratoma completely compressed the chest organs. No encephalocele was present. A 15-year-old woman, gravida 1, para 0, underwent an ultrasonogram at 27 weeks when fetal heart rate decelerations were detected. The ultrasound revealed hydrops and suggested a calcified left cardiac ventricular wall and diaphragmatic hernia. Autopsy of the stillborn female showed an 8.0 x 6.0 x 4.0-cm teratoma in the mediastinum, with small heart and lungs. A 23 2/7 weeks stillborn female was delivered to a 32-year-old woman, gravida 5, para 2, and noted to be hydropic. Ultrasound had suggested multiple anomalies and hydrops. Autopsy revealed a 23 g, 4.5 x 3.0 x 3.0-cm teratoma that filled the anterior mediastinum.

Conclusion: Congenital mediastinal teratoma may be associated with fetal death. It is within the differential diagnosis of nonimmune hydrops, particularly if a thoracic mass is detected on ultrasonography.