Autopsy proven CADASIL
There is diffuse anoxic-ischemic encephalopathy with many shrunken eosinophilic neurons present in the cerebral neocortex and hippocampus. Small and medium sized blood vessels of the leptomeninges and cerebral white matter show abnormal thickening of the vessel wall with loss of smooth muscle cells and an accumulation of granular eosinophilic, PAS positive material. These abnormal vessels are often associated with a dilated perivascular space and occasional deposits of hemosiderin. There is diffuse pallor of the cerebral white matter and a single chronic lacunar infarct present in the left parietal lobe. Blood vessels within the cerebral cortex, hippocampus and deep gray structures also appear abnormally thick-walled and frequently have dilated perivascular spaces. There are a number of small acute and chronic microinfarcts present. Vessels within the basal ganglia also show more hyaline thickening with some of them demonstrating mineral deposition (calcinosiderosis). The brainstem has only mild vascular abnormalities. In the cerebellum, there is a moderate degree of chronic cortical degeneration.
Electron microscopy on samples of cerebral white matter demonstrates blood vessels with decreased numbers of smooth muscle cells and large accumulations of granular osmophilic material.
Sections were immunostained for Notch-3 protein. The vessels show positive staining indicating the accumulation of mutant Notch3 protein and confirming the diagnosis of CADASIL.