Surgical treatment of the thrombosed vein of galen aneurysm.

Objective and Importance: Vein of Galen aneurysm is a rare congenital anomaly of cerebral circulation and occurs mainly in newborns and children. The spontaneously thrombosed vein of Galen aneurysm is especially rare and an uncommonly reported event.
Clinical Presentation: Two patients with a spontaneously thrombosed vein of Galen aneurysm were operated on at our institute. CT and MRI demonstrated space-occupying lesions of the pineal region and two other masses in the posterior fossa in the second case. The first described case should be referred to as the true type of aneurysm. The vascular malformation, revealed in the second case should be referred to as the false type. In this case the vein of Galen was enlarged to a gigantic size due to the blood drainage from the arteriovenous malformation supplying it from the inferior posterior cerebellar artery.
Technique: Thrombosed aneurysmal sacs were resected totally by subtentorial supracerebellar and median suboccipital approaches.
Conclusion: The authors report two cases of successful surgical resection of a thrombosed vein of Galen aneurysm in children. Diagnostic features are considered and the informative value of magnetic resonance imaging is stressed. The principles of choosing the right approach and dissection techniques of thrombosed aneurysms of the vein of Galen are described.