Progressive supranuclear palsy (PSP) is a neurodegenerative tauopathy 
characterized by Parkinsonism, vertical gaze palsy, and early falls. Lewy bodies 
(LBs) are detected in approximately 10% of PSP cases, but there is little 
information on the relationship of LBs to tau pathology. We determined the 
frequency of LBs in a large series of autopsy-confirmed cases of PSP and studied 
the density and distribution of LBs, including Parkinson disease stage, in cases 
with LBs (PSP/LBD). PSP/LBD was compared with pure LB disease (LBD), including 
assessment of neuronal loss in key brainstem nuclei. Immunohistochemistry for 
alpha-synuclein revealed LBs in 31 of 290 PSP cases (11%). One case had multiple 
system atrophy in addition to PSP and was excluded from further study along with 
2 PSP/LBD cases with concurrent Alzheimer disease. The 29 cases of PSP/LBD were 
compared with 30 cases of PSP and 24 cases of LBD. The age, sex, brain weight, 
Braak neurofibrillary tangle (NFT) stage, as well as counts of NFTs and senile 
plaques were not different among PSP, LBD, and PSP/LBD, but disease duration was 
longer in LBD. The Parkinson disease stage was similar, but the density of LBs 
in most subcortical nuclei tended to be greater in LBD than in PSP/LBD. In 
contrast, substantia nigra neuronal loss was greater in PSP/LBD than both PSP 
and LBD. Double immunostaining demonstrated alpha-synuclein and tau in different 
neurons with few exceptions. The findings suggest that LBs in PSP are similar in 
distribution to those in LBD and independent of tau pathology. The greater 
density of LBs in LBD compared with PSP/LBD may be the result of longer disease 
duration in LBD, whereas greater neuronal loss in the substantia nigra in 
PSP/LBD may be the result of vulnerability of this brain region to both disease 
processes.