[A case manifested overlapping neuropathologic features of both progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD)].

A 62-year-old man developed clumsiness, vertical ophthalmoplegia, right-side dominant parkinsonism, pyramidal signs, limb-kinetic apraxia and dementia. His brain MRI and SPECT revealed mild fronto-parietal atrophy and hypoperfusion predominately on the right side. At the age of 65, the patient died of sepsis. The duration of his illness was approximately 3 years. Clinical diagnosis was corticobasal degeneration (CBD). On neuropathological examination, there was no neuronal loss and many neurofibrillary tangles (NFTs) in the cerebral cortices. Basal ganglia and substantia nigra showed moderate to severe neuronal loss. And there were many NFTs and argyrophillic threads (threads) in the subthalamic nucleus and nuclei of the brainstem. These findings were almost compatible to those of PSP. However, the following findings were atypical for PSP, 1) mild atrophy and absence of gliosis in the tegmentum of the brain stem, 2) Mild neuronal loss in the subthalamic nucleus and the dentate nucleus without grumose degeneration. Furthermore, characteristic findings were noted on modified Gallyas-Braak stain. Numerous threads and many astrocytic plaques (AP) were shown in cerebral cortices, which were particular to CBD cases. So this case demonstrated neuropathological findings of both PSP and CBD. Therefore, it was difficult to classify this case as either PSP or CBD, and we diagnosed this case as a neuropathological overlapping case of both PSP and CBD.