Background: Craniofacial teratoma is a rare congenital malformation. We present a case of an intracranial expanding orofacial teratoma, where pathological examination revealed the findings of remarkable ultrasonographic signs and magnetic resonance imaging (MRI). Case Presentation: In the 23-week ultrasound examination, a solid cystic mass lesion was revealed in the craniofacial region. MRI showed that the mass had an intracranial extension and spread to the fetal face, and also revealed a marked nasopharyngeal obstruction by the mass. There was a growing tumor protruding from the fetus’s mouth. Slight polyhydramnios was also detected. Conclusion: In detecting prenatal anomaly, although the ultrasound is the first scan method applied, MRI in prenatal diagnosis is very useful for evaluating the extent, nasopharyngeal obstruction degree, and extension into the intracranial region of craniofacial teratoma.

Keywords: Prenatal ultrasound, prenatal MRI, fetal teratoma, fetal abnormality, polyhydramnios.