CASE 6

Courtesy of Almoosa Specialist Hospital

10-years-old male with ventriculoperitoneal shunt

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CASE 6 ANSWER

Dandy-Walker Malformation

A large simple cyst (yellow arrows) communicates with a dilated 4th ventricle (yellow star), expands the posterior fossa, leads to superior rotation of a hypoplastic vermis (green arrow), anteriorly displaces a flattened brain stem (red arrow), and causes obstructive hydrocephalus (white arrows). Note the presence of a ventriculoperitoneal shunt (black arrow).

Key Points

• The classic form manifests as a posterior fossa cyst communicating with a dilated fourth ventricle and leading to the superior rotation of a hypoplastic vermis, elevation of the torcular herophili, scalloping of the occipital bone.

• Hydrocephalus is a typical early manifestation.

• Commonly associated with other syndromic and non-syndromic features, such as cortical dysplasia, corpus callosum malformations, and other findings.