CORTICOBASAL DEGENERATION - WIDESPREAD ARGENTOPHILIC THREADS AND GLIAIN ADDITION TO NEUROFIBRILLARY TANGLES - SIMILARITIES OF CYTOSKELETALABNORMALITIES IN CORTICOBASAL DEGENERATION AND PROGRESSIVE SUPRANUCLEAR PALSY

A 57-year-old man had exhibited cortical sensory disturbance, rigidity , spasticity, dementia, alien hand, grasp reflex, supranuclear ophthal moplegia, pseudobulbar palsy, and neck dystonia for 4 years. Histologi cal examination of autopsied specimens revealed neuronal loss in the c erebral cortex, with ballooned neurons, subthalamic nucleus, substanti a nigra, basal ganglia, midbrain tegmentum, and the thalamus. There we re neurofibrillary tangles in the subthalamic nucleus and the substant ia nigra. Gallyas-Braak silver impregnation demonstrated numerous arge ntophilic tangles, threads, and a few argentophilic glia in the cerebr al cortex, subcortical white matter, particularly in the precentral gy rus, subcortical nuclei, and the brainstem. These argentophilic struct ures were largely positive for tau, and negative for ubiquitin, paired helical filaments, and phosphorylated neurofilament. Ultrastructurall y, 15-nm-wide straight tubules were observed in the neurons of the sub stantia nigra, globus pallidus, and the precentral cortex, coexisting with a few twisted tubules periodically constricted at 160- to 230-nm intervals. It was conclusively shown that Gallyas- and tau-positive cy toskeletal abnormalities occurred widely in brain of corticobasal dege neration. Both distribution and morphology of abnormal phosphorylated tau protein in corticobasal degeneration appear to resemble these feat ures in progressive supranuclear palsy. These findings suggest a commo n cytoskeletal etiopathological significance in corticobasal degenerat ion and progressive supranuclear palsy.