What are the neuropathologic findings of Parkinson disease (PD)?

Updated: Jan 24, 2019
  • Author: Robert A Hauser, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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Answer

No specific, standard criteria exist for the neuropathologic diagnosis of Parkinson disease, as the specificity and sensitivity of its characteristic findings have not been clearly established. However, the following are the 2 major neuropathologic findings in Parkinson disease:

  • Loss of pigmented dopaminergic neurons of the substantia nigra pars compacta

  • The presence of Lewy bodies and Lewy neurites

The loss of dopamine neurons occurs most prominently in the ventral lateral substantia nigra. Approximately 60-80% of dopaminergic neurons are lost before the motor signs of Parkinson disease emerge.

Some individuals who were thought to be normal neurologically at the time of their deaths are found to have Lewy bodies on autopsy examination. These incidental Lewy bodies have been hypothesized to represent the presymptomatic phase of Parkinson disease. The prevalence of incidental Lewy bodies increases with age. Note that Lewy bodies are not specific to Parkinson disease, as they are found in some cases of atypical parkinsonism, Hallervorden-Spatz disease, and other disorders. Nonetheless, they are a characteristic pathology finding of Parkinson disease.


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