Patient in a brain scan

Arachnoid Cysts

What Causes an Arachnoid Cyst?

Arachnoid cysts are thought to be present since birth and slowly grow over time. In many patients, these remain without symptoms and never require intervention. In select patients, these cysts continue to grow, causing pressure on the surrounding brain resulting in headaches as well as other neurological symptoms, depending on the location.

In some patients, arachnoid cysts can develop in the setting of other congenital brain malformations, such as Dandy-Walker Syndrome. The diagnosis can be made by high-resolution MRI, although in some instances CT cisternogram may be necessary to differentiate the cyst from normal circulating fluid.

Arachnoid Cyst Treatment

Arachnoid cysts can be treated with endoscopic surgery. If thought to be symptomatic, arachnoid cysts can be treated endoscopically with drainage into the deeper compartments of the brain. This approach can be helpful to prevent the need for a cystoperitoneal shunt placement. In select patients, existing cystoperitoneal shunts (usually placed in childhood) can be removed with endoscopic fenestration of the cysts.

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Last updated: April 6, 2020