SMALL ARTERIAL GRANULAR DEGENERATION IN FAMILIAL BINSWANGERS SYNDROME

A 55-year-old mildly hypertensive woman died after having developed a subcortical dementia during the past 9 years, with focal neurological signs. She presented at the age of 46 years with short episodes of diz ziness and diplopia, suggesting that transient ischemic attacks involv ed the posterior fossa structures. Over the next 8 years, she develope d difficulty in walking, urinary incontinence and seizures. On examina tion in 1989, she was severely demented. There was tetraparesis, bilat eral arm and leg spasticity with hyperreflexia and bilateral Babinski signs. She showed epilepsia partialis continua involving the eyes, lef t hemiface and limbs. CT showed hypodensity of the white matter and la cunes in the basal ganglia and centrum semiovale, moderate hydrocephal us with cerebellar and cortical atrophy. Clinical and radiological fea tures were similar to those of Binswanger's disease. Similar cases had occurred in the family affecting the patient's grandfather, father an d two brothers, suggesting an autosomal dominant hereditary disease. P ostmortem examination disclosed a Binswanger type of leukoencephalopat hy caused by a peculiar microangiopathy characterized by a slightly ba sophilic small arterial granular degeneration of the medial sheath ass ociated with the presence of ballooned smooth muscle cells with clear cytoplasm. Electron microscopic study revealed degenerative changes in the parietal vessels with notable increase of basal-membrane-type mat erial and electron-dense granular deposits. These lesions could. corre spond to a specific familial pathology of the small arteries of the br ain. They are identical to those reported in some patients with autoso mal dominant inheritance. For other patients with similar clinical fea tures and the same familial pattern, reported as ''hereditary multi-in farct dementia'' and ''cronic familial vascular encephalopathy'', ther e are no sufficient objective pathological facts to consider that they have the same disease. The absence of amyloid pathology in our case d ifferentiates it from the hereditary central nervous system amyloid an giopathies. Finally, patients with non-familial Binswanger's syndrome, but without hypertension, could exceptionally have the same vascular granular degeneration. Presumably, this vasculopathy of uncertain path ogenesis could be related to a metabolic disorder of the basement memb rane of smooth muscle cells.