Coexistence of PSP and MSA: a case report and review of the literature.

Progressive supranuclear palsy (PSP) is a neurodegenerative tauopathy characterized by Parkinsonism, vertical gaze palsy, and early falls. The neuropathology is characterized by neurofibrillary tangles, tufted astrocytes, and coiled bodies, but some brains show other pathologic processes. To investigate the frequency of alpha-synuclein pathology in PSP with immunohistochemistry and to report the clinical and pathological features of a case of PSP with concomitant Multiple system atrophy (MSA) (PSP/MSA), 290 cases of PSP were screened for alpha-synuclein pathology with immunohistochemistry. Double-labeling immunohistochemistry was performed on a case of PSP/MSA. Among the PSP cases screened for alpha-synuclein pathology, a single case of PSP/MSA was detected. The patient was an 86-year-old woman with clinical features consistent with PSP. She had no documented dysautonomia or cerebellar signs, and imaging studies were not diagnostic of MSA. Pathological examination showed tau-immunoreactive neuronal and glial lesions consistent with PSP as well as alpha-synuclein immunoreactive glial cytoplasmic inclusions diagnostic of MSA. Double-immunolabeling studies showed no co-localization of alpha-synuclein and tau in most neuronal and glial lesions. Based upon the findings in this case, the neuropathologic changes of PSP and MSA are distinct and independent processes, but they can occasionally coexist.