Trigonocephaly was previously described prenatally in association with severe abnormalities, mostly observed after 18 weeks of gestation. We describe our experience with this finding in early pregnancy, between 14 and 17 weeks of gestation. Our series includes 18 cases of trigonocephaly with several etiologies; trisomy 18, de novo translocation, thanatophoric dysplasia, and open spina bifida without hydrocephalus. Two fetuses had no other significant abnormalities and a spontaneous normalization of the skull shape was observed on follow-up. Both had normal genetic testing and postnatal outcome. These two cases represent a new phenomenon of an isolated transient form with normal outcome.
Keywords: prenatal diagnosis; transient; trigonocephaly.
© 2021 American Institute of Ultrasound in Medicine.