[Epidermoid cyst of the third ventricle. Report of a case].

We report a case of epidermal (or epidermoid) cyst, in a 36-year-old man which developed in the third ventricle. Clinical manifestations were headaches and memory disturbances. On CT scan the tumor occupied the entire third ventricle but was mainly developed on the left side. On CT reconstructed images, the floor of the third ventricle was clearly visible. Using a trans-ventricular approach, the tumor, closely related to the left part of hypothalamus, was totally removed. Later on, because of persistent hydrocephalus, a ventricular shunt was inserted. An aseptic meningitis occurred and resolved spontaneously. The patient exhibited a postoperative transitory Korsakoff's syndrome. Postoperative endocrine investigations showed hypopituitarism. Some intra-ventricular epidermal cysts have been reported, especially involving the fourth ventricle. Their development into the third ventricle is unusual, and in early reports their precise origin appears doubtful. Although they have no characteristic radiological features, the location of epidermal cysts is clearly defined by the CT scan and especially MRI. It would be possible to totally remove epidermal cysts of the third ventricle, avoiding the risk of recurrence.