Neurosyphilis masquerading as corticobasal degeneration.

We report on a patient with a syndrome resembling corticobasal ganglionic degeneration (CBD), including slight cognitive impairment, asymmetric akinesia, rigidity with myoclonus, and arm levitation, which can be one of the features of alien limb phenomenon; however, further diagnostic testing was consistent with neurosyphilis. Syphilis, "the great imitator," may also masquerade as CBD. Because neurosyphilis is treatable, it should be considered in the workup of patients with cognitive impairment and motor signs of CBD.