Case report: cerebellar hemi-hypoplasia.

Cerebellar hypoplasia is a prominent feature of fetal brain pathology. The lesion is rarely isolated or asymmetric. Various aetiological factors have been proposed. The frequency of cerebellar hypoplasia as a congenital defect in humans is unknown. A single case is described of unilateral cerebellar hypoplasia with intact vermis that was detected on prenatal ultrasound examination. Changes in the appearance of the abnormality over the course of the pregnancy raised the possibility of a disruptive vascular aetiology with destruction of normally formed structures. Prenatal ultrasound, post-delivery cranial ultrasound, and MRI images are presented to support the hypothesis.