This is a congenital brain malformation involving the cerebellum (an area at the back of the brain that controls movement) and the fluid-filled spaces around it. The key features of this syndrome are an enlargement of the fourth ventricle (a small channel that allows fluid to flow freely between the upper and lower areas of the brain and spinal cord), a partial or complete absence of the area of the brain between the two cerebellar hemispheres (cerebellar vermis), and cyst formation near the lowest part of the skull. An increase in the size of the fluid spaces surrounding the brain as well as an increase in pressure may also be present.The syndrome can appear dramatically or develop unnoticed.
Ultrasound findings include:
- Complete or partial agenesis of the cerebral vermis with flattened cerebral hemispheres.
- Large midline cystic structures in posterior fossa.