Autopsy case of pure akinesia showing pallidonigro-luysian atrophy.

A 60-year-old man developed levodopa-resistant pure akinesia. The patient gradually became more akinetic without accompanying gaze palsies, nuchal dystonia, or other parkinsonian features such as rigidity or tremor. At the age of 71, he died of bronchopneumonia. Neuropathologically, bilateral marked neuronal loss and gliosis were restrictedly observed in the globus pallidus, substantia nigra and corpus luysii, whereas mild gliosis without neuronal loss was found in the brain stem. With Gallyas-Braak silver stain, numerous argyrophilic fibrous structures partly surrounding glial nuclei were observed in the three major affected regions. With Bodian stain, however, they were rarely recognized. The structures were partly positive for tau protein. Rare neurofibrillary tangles were found in the three areas and brain stem. They were relatively more numerous but still sparse in the hippocampus and the parahippocampus. The present case was diagnosed as having pallidonigro-luysian atrophy based on two characteristic findings: (i) the distribution of lesions showing neuronal loss with gliosis; and (ii) significant presence of tau-positive argyrophilic fibrous structures related to glia but with the absence of neurofibrillary tangles in the major affected regions and the brain stem. As our present case uniquely showed pure akinesia for the whole clinical course, it is noteworthy to report it here with a full neuropathological evaluation. In addition, a moderate number of diffuse plaques positive for beta-amyloid were distributed in the thalamus.