Two cases of XXXX derived from arachnoid membrane over the vein of Galen without dural attachment.

@entity1 @entity979 @entity5 @entity1653 @entity1296 @entity10
BACKGROUND: We present two rare cases of @entity979 . These @entity5 are the first reported cases of dura-unrelated @entity1653 originating from the arachnoid membrane over the vein of Galen (AMG). CASE DESCRIPTION: In Case 1, a 37-year-old @entity1 presented with a progressing @entity10 . Magnetic resonance imaging (MRI) showed a large @entity5 in the pineal region, displacing the vein of Galen upward. Angiography disclosed occlusion of the vein of Galen, with deep venous flow draining through the veins on the right medial surface of the occipital lobe to the superior sagittal sinus. In Case 2, a 67-year-old @entity1 presented with @entity1296 . MRI demonstrated a large mass in the pineal region, displacing the vein of Galen inferiorly. Angiography disclosed occlusion of the vein of Galen, with deep venous flow draining through the collateral venous channel into the transverse sinus. Both @entity5 were totally excised (Simpson Grade III for Case 1, Grade I for Case 2) via a left occipital transtentorial approach. No dural attachment was recognized in either case, but the @entity5 in Case 1 was firmly adherent to the inferior portion of the AMG, while that in Case 2 was attached to the superior portion of the AMG, but remained dissectible. CONCLUSIONS: We reported two cases of @entity979 originating from the arachnoid membrane over the vein of Galen, resulting in @entity1653 without dural attachment. These @entity5 can be totally resected by careful dissection of the @entity5 from the arachnoid membrane surrounding the vein of Galen.
