Ex-Utero Intrapartum Treatment for a Fetal Cervical Teratoma with Mediastinal Extension: A Case Report.

BACKGROUND Ex-utero intrapartum treatment (EXIT)-to-airway is a complex perinatal procedure performed in the case of potential postnatal airway obstruction. It requires an experienced multidisciplinary team and meticulous surgical planning based on fetal imaging. This report describes the use of EXIT-to-airway for a large cervical teratoma with extension into the mediastinum. CASE REPORT At 35 weeks' gestation, a 29-year-old woman presented to our fetal care center with significant polyhydramnios. The fetus was subsequently diagnosed with a large cervical mass extending into the mediastinum. An EXIT-to-airway procedure was performed at 36 weeks' gestation. The neonate remained intubated while postnatal imaging was obtained. At day of life 3, resection of the teratoma was performed via a combined cervical and mediastinal approach. Pathology confirmed a mature teratoma. The neonate's hospital course was complicated by aspiration with feeding, requiring a gastrostomy tube, and she was discharged on day of life 40. CONCLUSIONS While cervical teratoma is a well-established indication for the EXIT procedure, this case is notable for its late third-trimester diagnosis and the rare extension of the mass into the mediastinum, which necessitated a dual surgical approach. It highlights the importance of maintaining a broad differential diagnosis in the setting of recurrent third-trimester polyhydramnios and demonstrates the critical role of multidisciplinary planning in optimizing outcomes when airway compromise is anticipated. This case contributes to the growing body of evidence supporting the expanded utility of EXIT-to-airway for complex cervicomediastinal masses.