Definition:  This teratoma originates from the facial bones, especially the palate, the sphenoid, and the ethmoid.

Prevalence: Extremely rare. There are few case reports in the literature[i].

Ultrasound features: Solid or solid and cystic structures, sometimes huge in appearance are protruding from the fetal oral cavity. Calcifications may appear. Polyhydramnios is frequent due to  pharyngeal obstruction.

Prognosis:  The outcome depends on the size of the tumor and degree of airway obstruction. Death may occur after birth, due to asphyxia because of airway obstruction. Solid or solid and cystic structures, sometimes huge in appearance are protruding from the fetal oral cavity.  Calcifications may appear. Polyhydramnios is frequent due to pharyngeal obstruction.

Reference:

[i] Chervenak, F.A. Tortora, M., Moya, F.R. Antenatal sonographic diagnosis of epignathus. J Ultrasound Med 19984; 3:235