Substantia nigra in progressive supranuclear palsy, corticobasal degeneration, and Parkinsonism-dementia complex of Guam: Specific pathological features

Disease-specific findings in the substantia nigra were examined in cases of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD). and parkinsonism-dementia complex of Guam (PDC); diseases in which the patient s exhibit dementia and parkinsonism. with neurofibrillary tangles (NFTs) an d glial tangles composed of hyperphosphorylated tau. Loss of pigmented neur ons was extremely severe in these 3 diseases, and decrease of the nonpigmen ted neurons was severe in PSP and CBD. On the other hand, in PDC the decrea se of the nonpigmented neurons was different in each patient. Topographical ly, in PSF the nonpigmented neurons were particularly depleted in the ventr al part and relative preservation of the pigmented neurons was observed in the medial part at the level examined. Many NFTs were observed in PDC. Alth ough the number of NFTs was small. many pretangles were seen in the neurons in CBD. Granular and hazy astrocytic inclusions were identified exclusivel y in PDC. Numerous argyrophilic neuropile threads were identified in CBD an d PSP. but these were few in PDC. Many foamy spheroid bodies as well as coi led bodies were observed in PSP and CBD, but only a few were observed in PD C. In conclusion, PDC is a disease that is distinctly different from PSP an d CBD. It is possible to differentiate between PSP and CBD by the occurrenc e of many pretangles in CBD, but some similarities between these 2 diseases indicate the existence of common pathological mechanisms.