Morphological overlap between corticobasal degeneration and Pick's disease: a clinicopathological report.

An 81-year-old woman died after a 3-year history of a progressive nondementing akinetic-rigid syndrome. Initially, there was a moderate response to levodopa treatment. Subsequently she developed postural tremor, loss of upward gaze, and frequent falls suggestive of Steele-Richardson-Olszewski syndrome (SROS). Macroscopical examination showed depigmentation of substantia nigra and locus ceruleus. Histology revealed occasional swollen achromatic neurons predominantly in frontal cortex, small cortical neurofibrillary tangles, brain stem basophil (corticobasal) inclusions, and Pick bodies. The coexistence of these histopathological markers raises questions concerning their specificity and the basis of a morphological distinction between corticobasal degeneration and Pick's disease.