Aqueductal stenosis due to mesencephalic venous malformation: case report.

The authors report the case of a 43-year-old woman with a venous malformation of the mesencephalon occluding the sylvian aqueduct. Neuroradiological investigations suggested aqueductal stenosis, while the presence of a venous malformation was diagnosed by both magnetic resonance imaging and an angiogram, and was visualized using a neuroendoscope. This is the first reported instance of a venous malformation being observed in situ and the subependymal course taken.