Ex utero intrapartum treatment (EXIT) procedure for the second twin with neck mass in a twin pregnancy with vertex/breech presentation.

We report a case of a dichorionic diamniotic twin pregnancy where twin B was diagnosed with a large multi-loculated exophytic cystic neck mass arising from the right side with involvement of the right proximal upper limb and significant mass effect on the trachea diagnosed during antenatal MRI. After multidisciplinary discussion, an ex utero intrapartum treatment (EXIT) procedure was planned given concerns about airway obstruction in twin B. Successful EXIT was performed with the delivery of twin A first, followed by an intraoperative external cephalic version of twin B and subsequent delivery of the fetal head and intubation on maternal circulation.