Corticobasal degeneration: an autopsy case clinically diagnosed as progressive supranuclear palsy

We report an autopsy case diagnosed clinically as progressive supranuclear palsy (PSP), but neuropathologically confirmed as corticobasal degeneration (CBD). A 56-year-old Japanese woman slowly developed parkinsonism, dementia, character change, followed by vertical gaze palsy and dystonia. Brain MRI demonstrated diffuse cerebral atrophy with severe shrinkage of the brain stem tegmentum. The SPECT images using 123I-IMP disclosed symmetrical hypoperfusion in the frontal lobes. She died of respiratory failure at the age of 71. Gross inspection of the brain showed diffuse, symmetrical atrophy of the cerebrum and marked atrophy of the Luysian body, globus pallidus, substantia nigra and nuclei of the brain stem tegmentum. Microscopically, neuronal loss and fibrillary gliosis were observed in the Luysian body, globus pallidus, substantia nigra and nuclei of the brain stem tegmentum. The cerebellar dentate nucleus showed mild neuronal loss with some grumose degeneration. Neurofibrillary tangles were found only in the Luysian body, substantia nigra and raphe nuclei, whilst tau-positive inclusions were observed more extensively. Astrocytic plaques and swollen achromatic neurones were found in the postcentral gyrus. There were no tuft-shaped astrocytes in the brain. The clinicopathological similarities and differences between PSP and CBD are discussed.