Discrepancy between clinical and pathological diagnoses of CBD and PSP

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) are often clinically confused with each other. Moreover, the discrepancy between clinical and pathological diagnoses of CBD and PSP are still controversial. We report here two atypical cases of PSP and CBD. A 73-year old woman was admitted with right hand rigidity, limb kinetic apraxia and cortical sensory loss. Brain atrophy, hypoperfusion and hypometabolism predominantly in the left frontoparietal lobes indicated CBD clinically. Pathological studies revealed neuronal loss and spongy change without ballooned neurons (BN) in the cerebral cortex. Modified Gallyas-Braak (G-B) staining revealed neurofibrillary tangles (NFTs) and tufted astrocytes, indicating pathological diagnosis of PSP. A 75-year-old man admitted with vertical gaze palsy, neck dystonia, parkinsonism and dementia. Atrophy of the frontal lobes and tegmentum of the midbrain and symmetrical frontal hypoperfusion in SPECT indicated PSP. However, neuronal loss and BN in the frontal lobes and clusters of astrocytic plaques indicated CBD pathologically. The G-B staining was useful for differentiating between CBD and PSP, but our atypical cases bring up a new issue about differential diagnosis of CBD and PSP.