[Prenatal diagnosis of isolated otocefalia. Usefulness of three-dimensional ultrasound]. / Diagnóstico prenatal de otocefalia aislada. Utilidad de la ecografía tridimensional.

Otocephaly is a rare and lethal congenital malformation characterized by the presence of agnathia, microstomia, aglossia and synotia. Despite its frequent association with severe malformations, diagnosis in the few published cases is usually made at III trimester. In this case, three-dimensional ultrasound scan was performed in a Chinese primigravida with no remarkable personal nor familiar history since mandible was difficulty visualized with two-dimensional sonography at 21 weeks of gestation. Multiplanar and rendering mode showed the typical cervicofacial features of otocephaly without associated malformations. After parental counselling, they opted for termination of pregnancy and necropsy confirmed our prenatal findings. Our case shows the usefulness of three-dimensional ultrasound in assessing fetal cervicofacial pathology. Volumetric capture allows a delayed study of fetal anatomy and multiplanar mode offers the reconstruction of views whose achivement is difficult with conventional 2D ultrasound. Surface rendering provides excellent spatial vision and enables parents to understand the severity of the malformation thus helping with their decisions.