Superficial siderosis: a potential diagnostic marker of cerebral amyloid angiopathy in Alzheimer disease.

BACKGROUND AND PURPOSE Superficial siderosis of the central nervous system results from chronic bleeding in the superficial layers of the cortex and spinal cord. In cerebral amyloid angiopathy (CAA), there is amyloid deposition in meningeal and meningo-cortical arteries and capillaries, predisposing them to rupture. CAA is frequently associated with Alzheimer disease (AD). METHODS We report a series of 3 AD patients with MRI evidence of superficial siderosis. Two had neuropathological examination confirming superficial siderosis, AD, and CAA. CONCLUSIONS Superficial siderosis should be recognized within the spectrum of AD with CAA and considered as a possible antemortem diagnostic feature.