Presentation
Weakness of the right side of the body since two days.
Patient Data
Age: 70 years
Gender: Female
From the case:
Posterior fossa arachnoid cyst
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Large extra-axial lesion of the posterior fossa with CSF-like density. No surrounding edema or mass effect on the fourth ventricle. No solid nodules. No CT findings of cerebral vascular insufficiency. CT findings suggest a posterior fossa arachnoid cyst type 2b.
Case Discussion
Posterior fossa arachnoid cysts can be classified into four subgroups as follow:
- 1a: midline inside the 4th ventricle treated by shunting or endoscopic fenestration
- 1b: midline outside the 4th ventricle, treated by surgery
- 2a: off-midline within the cerebellopontine angle treated by surgery f endoscopic fenestration
- 2b: off-midline either retro-cerebellar or intracerebellar treated by surgery