Presentation
Headache and blurring of vision.
Patient Data
Age: 30 years
Gender: Male
From the case:
Blake's pouch cyst
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Moderate hydrocephalus with dilated 4th ventricle continuous with infra-cerebellar cyst. The cerebellar vermis is compressed yet it appears intact and not rotated. Note the hyperdynamic signal void flow through the aqueduct of Sylvius and 4th ventricle.
Case Discussion
Blake's pouch cyst is caused by lack of fenestration of the Blake pouch, resulting in absence of communication between the fourth ventricle and the subarachnoid space. This will lead to cyst formation below and posterior to the vermis, that communicates with an open fourth ventricle.
The cerebellum has a normal size and shape.