[Clinicopathologic study of progressive subcortical vascular encephalopathy of Binswanger type (PSVE)].

To investigate the histopathological basis of white matter pallor on myelin staining in PSVE, the frontal white matter was examined by electron microscopy in 7 cases with PSVE. The number of nerve fibres per unit area of the white matter was significantly less in PSVE compared with that in the control group or in senile dementia of Alzheimer's type (SDAT). Nerve fibers in PSVE had a tendency to have thinner myelin sheaths than in the control group or in SDAT, but the difference was not significant. The white matter pallor in PSVE is mainly based on the loss of nerve fibres. The dementia in PSVE is probably related to the loss of nerve fibres in the cerebral white matter. A sum of oligodendrocytes and astrocytes per unit area decreased in the area with white matter pallor. Main stem of cerebral arteries, leptomeningeal arteries, medullary arteries in the cortex, and small arteries or arterioles in the cerebral white matter were studied pathologically in 22 elderly patients with PSVE. Not only the severe hyalinotic changes of arterioles in the cerebral white matter, but also the diffuse atherosclerotic lesions in main stem of cerebral arteries and/or the stenotic lesions in leptomeningeal arteries were the characteristic arterial changes of PSVE. Angionecrosis was observed in 70% of the PSVE patients. To substantiate my hypothesis that PSVE in the elderly can be induced by the repeated hypotension or the greater variability of the casual blood pressure in the hypertensives, I studied retrospectively the casual blood pressures in PSVE.(ABSTRACT TRUNCATED AT 250 WORDS)