Third Ventricle Colloid Cyst as a Cause of Sudden Drop Attacks of a 13-Year-Old Boy

Colloid cysts are mucous-filled masses with an outer fibrous layer. these cysts are rare developmental malfor-mation and not a true neoplasm. they usually found incidentally and are asymptomatic; but in some cases may associate with rapid neurologic deterioration, herniation, and sudden death. recognition of this rare but im-portant diagnosis may result in decreasing mortality. in this report, we presented a 13-year-old boy with com-plaint of two times drop attack and final diagnosis of colloid cyst in the third brain ventricle.