label: colloid cysts of third ventricle
label_lc: colloid cysts of third ventricle
description: Colloid cysts of the third ventricle are non-cancerous brain lesions. The third ventricle is a cavity in the brain that is filled with cerebral spinal fluid (CSF). Colloid cysts can cause blockages resulting in a build up of CSF in the brain (hydrocephalus) and increased pressure. Some colloid cysts are asymptomatic while others cause neurological symptoms, such as headaches, swelling of the optic nerve (papilledema), and drop attacks. When symptoms are present onset tends to be in the third to sixth decade of life. While uncommon, symptoms of colloid cyst can become life threatening.