Spontaneously healed vein of Galen aneurysms. Clinical radiological features.

Vein of Galen aneurysms demonstrate a high tendency to thrombose, as extensive thrombophlebitis of the dural sinuses and deep venous system occurs frequently. This may be explained by the frequent detection of venous anomalies and retention of embryonic venous patterns such as the median prosencephalic vein. Twenty-one cases were reviewed (19 from the literature, 2 of our own cases): no typical syndrome for thrombosed aneurysm of the vein of Galen could be found; therefore, a preliminary diagnosis of clotted vein of Galen aneurysm was made in only half the cases. In all the remaining ones, pineal or III ventricle masses were suspected. Nevertheless, crescentic rimlike calcifications in the region of the vein of Galen can be found in 50% of cases. Only in half of the cases did angiography demonstrate the malformation filled by contrast medium, while in the remaining cases not only the aneurysm but also the deep Galenic venous system failed to opacify. Computed tomography and magnetic resonance scans demonstrated masses with high density/intensity values, with varying degrees of calcification. Knowledge of this pathological entity is important in order to avoid unnecessary surgical procedures.