What are arachnoid cysts?

What are arachnoid cysts?

Arachnoid cysts are fluid-filled sacs that grow on the brain and spine. They are not tumors, and they are not cancerous. On rare occasions, if they grow too big or press on other structures in the body, they can cause brain damage or movement problems.

Most arachnoid cysts appear at birth or after childhood head trauma, and the vast majority of cysts don’t cause symptoms. When symptoms do appear, they vary from person to person. They may include headaches, dizziness, nausea, vomiting or seizure.

Treatment depends on where the cyst is and if it’s growing or causing symptoms. If treatment is necessary, providers usually drain the cysts or open them surgically to the surrounding spaces.