Colloid cysts of the third ventricle are benign tumors that may lie dormant and be found incidentally at autopsy or on CT or MRI examination. By contrast, in some cases they may cause severe, acute obstruction to the flow of cerebrospinal fluid, leading to coma and death. More commonly, they present as recurrent headaches, ataxia, nausea and vomiting, depression, memory loss, and emotional lability, all of which are associated with chronic hydrocephalus. Symptomatic colloid cysts are seen most commonly in middle life, but they also occur in childhood and old age (summary by Partington and Bookalil, 2004). [from
OMIM]