The distribution of Alzheimer's neurofibrillary tangles and gliosis in chronic subacute sclerosing panencephalitis

In two cases of clinically verified chronic subacute sclerosing panencephalitis (case 1, male, 15 years with a 9-year history; case 2, male, 20 years with a 9-year history) numerous Alzheimer's tangles (AT) were identified throughout the cerebral cortex (containing paired helical filament on electron microscopical examination). The brains were severely atrophic with hydrocephalus ex vacuo, occasional scattered microglial nodules, scant perivascular inflammatory infiltrates and demyelination. Only in case 1 were a few atypical intranuclear inclusion bodies noted. In the six-layered neocortex, a distinct distribution pattern of AT was observed; these lesions were mainly seen in laminae II, III and V (laminar distribution). The glial fibrillary acidic protein stain displayed extensive laminar gliosis mainly of the layers I, IIa, IV and VI; layers III and V, largely occupied by the AT, remained conspicuously spared from gliosis (especially the lamina III). Gliosis was prevalent in the white matter which was atrophic and shrunk. In the hippocampus, the AT involved many pyramidal neurons and, in this layer gliosis was lighter than in the surrounding white matter. In case 2, AT were present in the nucleus of Meynert, hypothalamus and in raphe centralis of the upper brain stem. Overall, the distribution of AT resembled that seen in Alzheimer's disease and aging; however, the senile plaques, vascular amyloidosis and granulovacuolar change were totally absent in both cases.