Holoprosencephaly and cyclopia visualized by two- and three-dimensional prenatal ultrasound.

We report on the ultrasound (US) detection of holoprosencephaly with cyclopia at a gestational age of 16 weeks. The sonographic diagnosis was based on the intracranial finding of fused thalami with no visible midline structures and facial abnormalities, including cyclopia and proboscis. We evaluated the fetal face by 3-dimensional (3D) transabdominal US and were able to identify the cyclopia below the proboscis. These findings are characteristic of alobar holoprosencephaly. With the informed consent of the patient, the pregnancy was terminated by prostaglandin induction after proper counseling. Chromosome study of the abortus revealed a normal karyotype (46, XY). Postmortem examination of the abortus confirmed the presence of cyclopia and a proboscis. The use of 3D prenatal US made additional diagnostic images possible.