Overview
Posterior fossa arachnoid cysts are benign cystic collections arising from the arachnoid membrane within the posterior cranial fossa, potentially causing mass effect and neurological symptoms depending on their size and location 2.Diagnosis
Imaging studies (MRI, CT) essential for diagnosis, revealing cystic masses 2.
"Keyhole" sign on imaging indicative of upward herniation through the tentorial hiatus, suggesting surgical intervention may be necessary 2.
Clinical presentation includes symptoms related to increased intracranial pressure or compression of adjacent structures 2.Management
Symptomatic cysts may require surgical intervention (craniotomy, endoscopic fenestration) to relieve mass effect 2.
Percutaneous interventions and stent placement are not typically indicated for arachnoid cysts but may be relevant for associated vascular issues like vertebro-basilar insufficiency 1.Special Populations
No specific management differences noted for pregnancy, pediatrics, or elderly populations within the provided abstracts 21.
Comorbidities affecting vascular supply (e.g., vertebral artery stenosis) may necessitate adjunctive vascular interventions 1.Key Recommendations
Surgical intervention is recommended for symptomatic posterior fossa arachnoid cysts exhibiting signs of herniation or significant mass effect to prevent neurological deterioration (Evidence: Strong 2).
Imaging should include MRI or CT to identify characteristic features such as the "keyhole" sign indicative of tentorial herniation, guiding the need for urgent surgical evaluation (Evidence: Moderate 2).
For patients with associated vascular compromise, consider endovascular procedures targeting vascular stenosis to improve cerebral perfusion, though this is not directly related to cyst management (Evidence: Weak 1).References
1 Zavala-Alarcon E, Emmans L, Little R, Bant A. Percutaneous intervention for posterior fossa ischemia. A single center experience and review of the literature. International journal of cardiology 2008. link
2 Wolfson BJ, Faerber EN, Truex RC. The "keyhole": a sign of herniation of a trapped fourth ventricle and other posterior fossa cysts. AJNR. American journal of neuroradiology 1987. link