Focal asymmetric cortical atrophy with ballooned neurons, nigral degeneration, and tau-positive neuronal and glial lesions in both the gray and white matter, particularly astrocytic plaques in the affected cerebral cortex, are characteristic features of corticobasal degeneration (CBD). Since the clinical manifestations of CBD are diverse, several neurological diseases can present with clinical findings that are thought to be specific to CBD. These clinical conditions are referred to as corticobasal syndrome (CBS). CBS includes Alzheimer's disease, progressive supranuclear palsy, Pick's disease, Lewy body disease, frontotemporal lobar degeneration, and Creutzfeldt-Jakob disease. In cases of clinically diagnosed CBS, the consistent histopathological finding appears to be asymmetric frontal and parietal cortical degeneration.