Pseudo-tumoural aneurysm in the third ventricle: Report of three cases.

3 cases of giant sacciform aneurysm developed in the third ventricle are reported. They were observed in patients over 50 years. Clinical symptomatology evoked a tumor rather than a vascular malformation. Diagnosis can be difficult even with angiography and CT scan performed conjointly when the giant aneurysm is completely thrombosed. The size of the lesion is not a matter of age since 10% at least of these giant aneurysms are observed in children. They are mainly seen along the large arteries at the neck or at the base of the brain; the high focal pressure of the blood flow at these levels can perhaps play a role in the usual site of these lesions. Surgical treatment remains a challenge when the aneurysm is burrowed deep into the third ventricle and when being thrombosed, it is mainly symptomatic by its mass.