hereditary disease colloid cysts of third ventricle https://rarediseases.info.nih.gov/diseases/9878/colloid-cysts-of-third-ventricle https://www.malacards.org/card/colloid_cysts_of_third_ventricle 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. OMIM:609363 UMLS:C0266481 MEDGEN:82744 MONDO:0012259 colloid cysts of third ventricle MESH:C535966