Widespread dilatation of perivascular spaces: a leukoencephalopathy causing dementia.

A 68-year-old demented woman had widespread dilatation of perivascular spaces in the cerebral white matter for at least 12 years. There were no micro-infarcts, but some vessel walls in the white matter were thickened by a loose fibrosis. Our case does not correspond to Binswanger's disease or any other known vascular leukoencephalopathy. The longstanding evolution points to a nonfamilial leukoencephalopathy of probable vascular origin.