Presentation
Enlarged head, developmental delay.
Patient Data
Age: 6 months
Gender: Male
From the case:
Dandy-Walker malformation
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The classic triad of the disease is evident:
1. severely hypoplastic vermis with cephalad rotation of the vermian remnant
2. cystic dilatation of the fourth ventricle extending posteriorly to an enlarged posterior fossa
3. significantly enlarged posterior fossa with torcular-lambdoid inversion and open posterior fontanel and thinning of adjacent bones
Marked communicating chronic hydrocephalus.
Case Discussion
Dandy-Walker malformation is the most common posterior fossa malformation (about 1 per 30,000). It can be an isolated entity or associated with other anomalies.
The imaging differential diagnosis can be mega cisterna magna and large arachnoid cyst.