The treatable dementia of Sjögren's syndrome.

Progressive dementia developed during a 15-month period in a 56-year-old woman with serologically and clinically documented primary Sjögren's syndrome. Findings from magnetic resonance imaging and angiography were normal, but a brain biopsy disclosed perivascular lymphocytic inflammation in leptomeningeal and parenchymal vessels. Treatment with high-dose corticosteroids produced rapid and nearly complete resolution of the dementia.