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 thi
ckened by a loose fibrosis. Our case does not correspond to Binswanger
's disease or any other known vascular leukoencephalopathy. The longst
anding evolution points to a nonfamilial leukoencephalopathy of probab
le vascular origin.