EXIT procedure for fetal mediastinal teratoma with large pericardial effusion: a case report with review of literature.

Background: Large mediastinal teratomas in the fetus are rare and can present with direct compression of intrathoracic structures as well as pericardial and pleural effusions. Mediastinal fetal teratoma may be detected as a mass in the chest during a routine prenatal ultrasound. Because of the pressure on mediastinal structures it may result in non-immune fetal hydrops (NIFH) and polyhydramnios. The development of hydrops may lead to fetal demise. Timely obstetric and/or surgical intervention is important to improve survival in this patient population. Case review: We report a case of a large mediastinal teratoma in a fetus who presented with a large pericardial effusion at 28 weeks gestation. The fetus developed NIFH at 31 weeks gestation. The fetus was successfully managed with an ex utero intrapartum therapy (EXIT) procedure which involved pericardiocentesis and surgical resection of the large teratoma. Histological examination revealed an encapsulated immature teratoma. Discussion: Mediastinal teratomas are usually detected by routine second- and third-trimester ultrasound. Large teratomas have been described to present with airway compromise and NIFH. Some cases have been managed by postnatal surgery and rare cases by EXIT procedure. Conclusions: This is the first reported case of a fetal mediastinal teratoma and severe pericardial effusion who developed NIFH, in whom EXIT procedure was successfully employed to simultaneously drain the effusion and resect the tumor.