Presentation
Recurrent seizure since infanthood. VP shunt insertion.
Patient Data
Aneurysmal dilatation of a midline venous pouch, most likely median prosencephalic vein (32mm maximum diameter), with dilated straight sinus, the bilateral sigmoid sinus, the bilateral transverse sinus, the confluence of sinuses (torcula herophili – 35.2mm), and the right jugular bulb (12mm). No significant dilation of the superior sagittal sinus but dilated cortical veins drains to the superior sagittal sinus.
Significant brain volume loss with diffuse subcortical white matter and bilateral basal ganglia hyperintensities on T1 with areas of FLAIR hyperintensities in the right frontal cortex and thalami. Thinning of the corpus callosum and collapsed supratentorial ventricular system.
Vein of Gallen aneurysmal malformation - choroidal type, with multiple tortuous dilated feeding arteries of the posterior choroidal arteries, branches of the posterior cerebral arteries, thalamic perforators, and pericallosal arteries with draining veins in keeping with arteriovenous malformation.
Secondary venous congestion of the bilateral cavernous sinus (L>R), ophthalmic veins, and tributaries of the bilateral external jugular vein.
Gyral calcifications indicate diffuse cortical laminar necrosis and collapsed ventricles with a right-sided VP shunt in the setting of global brain atrophy.
Case Discussion
Vein of Galen aneurysmal malformation is a type of intracranial arteriovenous fistula of the median prosencephalic vein that can result in left to right shunt and high-output heart failure. They can be mural type which is common in infants and children or choroidal type as in this case with multiple feeders which is common in neonates.
The child presented with seizure disorder since infanthood and hydrocephalus from venous hypertension (not seen in the images), but VP shunt was seen in the CTA images, which is not the supposed typical treatment in this case. Hydrocephalus is not shunted in the case of VGAMs, as shunting may exacerbate ischemia that was demonstrated in this case by a diffuse cortical laminar necrosis and increases the risk of intraventricular hemorrhage.
Endovascular intervention has significantly improved the prognosis of VGAM, though the mode and timing of intervention differs for different age groups and types of VGAM. For choroidal VGAM, embolization is deferred until 6 months of age, provided there is no cardiac failure that is refractory for medical management, as cardiac failure has a prognostic value in the management of VGAM.
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