Dandy-Walker variant

Case contributed by Dr Aditya Shetty


One episode of generalized tonic-clonic seizure; large head size.

Patient Data

Age: 2 years
Gender: Male

A cystic area of CSF density is noted in the posterior fossa, with a "keyhole" appearance. 

This cystic area is in continuation with the fourth ventricle.

Vermian hypoplasia is also noted with gross hydrocephalus.

Annotated image

The "keyhole connection sign" (white dashes) refers to the abnormal connection of the cisterna magna and the posterior aspect of the fourth ventricle. 

Case Discussion

A case of Dandy-Walker variant (less severe type as part of the Dandy-Walker continuum) with gross hydrocephalus. A 'keyhole' appearance is formed due to vermian hypoplasia and the cystic area extending into the 4th ventricle

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Case information

rID: 27797
Published: 20th Feb 2014
Last edited: 14th Aug 2019
Tag: shetty
Inclusion in quiz mode: Included

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