Dandy-Walker malformation

Case contributed by Assoc Prof Frank Gaillard


Increasing head circumference.

Patient Data

Age: 2 years
Gender: Male

MRI brain

MRI of the brain of a child demonstrates an abnormal posterior fossa. The vermis is hypoplastic and rotated upwards, below which a large cystic space continuous with the fourth ventricle is present. The posterior fossa is elevated. The aqueduct appear narrowed and there is prominent obstructive hydrocephalus. The over-all size of the skull is increased. 


MRI brain

A flow void is now seen through the floor of the third ventricle with reduced dilatation of the third and lateral ventricles (implied by reduction in upward bowing of the corpus callosum). 


Annotated images

Pre third ventriculostomy there is marked distention of the third ventricle with ballooning out of the recesses:

  1. supraoptic (orange arrow)
  2. infundibular (green arrow)
  3. pineal (red arrow)

Post third ventriculostomy has been performed with flow seen through the floor of the third ventricle (yellow arrow). Funnelling of the superior part of the aqueduct (blue arrow) is seen in keeping with aqueduct stenosis due to extrinsic compression. 

Case Discussion

This case illustrates a classic Dandy Walker malformation with associated aqueduct stenosis and obstructive hydrocephalus, a common associated feature (although not part of the triad 1. hypoplasia of the vermis with cephalad rotation, 2. cystic dilatation of the fourth ventricle, 3. enlarged posterior fossa )

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Case information

rID: 15808
Published: 12th Nov 2011
Last edited: 16th Oct 2019
Inclusion in quiz mode: Included

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