The third ventricle is located between the two sides of the thalamus and is deep, with the choroid plexus and the internal cerebral vein at its top and the optic cross at its bottom, the funnel, the gray nodes, the papillae and the lower thalamus. The third ventricle is connected to the left and right lateral ventricles by interventricular foramina and to the fourth ventricle by the midbrain aqueduct. The third ventricle is an important part of the cerebrospinal fluid circulation pathway, and if a lesion occurs, it can lead to blockage and hydrocephalus. Tumors originating in the third ventricle include gliomas, teratomas, craniopharyngiomas, lymphomas, cholesteatomas, and glial cysts, and are most commonly seen in children and young adults. The most common clinical symptom is headache, as hydrocephalus can cause an increase in intracranial pressure. Preoperative diagnosis is usually provided by enhanced MRI.