Direct drainage of extracranial arteries into the superior sagittal sinus associated with dementia.

A 62 year-old-man suffered from progressive dementia for the last 5 years of his life. Angiography disclosed draining of multiple extracranial, galeal arteries directly into the superior sagittal sinus with retrograde filling of cerebral veins. At necropsy there was arterialization of the walls of the sinus and a multichannelled lumen in its middle third. The sinus was not distended, the dura normal, and no angioma was found. The leptomeninges and the cerebral white matter contained excessively distended veins, some with thickened fibrotic walls. Many arteries in the arterial white matter were mineralized. There were widespread patches of incomplete demyelination about these abnormal vessels. The lesion was classified as a developmental anomaly with direct shunting of extracranial arteries into the superior sagittal sinus.