Motor neuron disease-inclusion dementia presenting as cortical-basal ganglionic degeneration.

The frontotemporal dementias are a group of relatively new and evolving clinical and pathologic entities. The predominant frontal-temporal atrophy causes a variety of clinical syndromes, usually dominated by disturbances in behavior, mood, and speech. The motor neuron disease-inclusion dementia (MNDID) subtype is characterized by the accumulation of specific intraneuronal ubiquitin-immunoreactive inclusions with the complete absence of tau immunoreactivity. We present a patient with the clinical and neuroimaging characteristics of a highly asymmetric neurodegenerative condition distinguished by limb rigidity, bradykinesia, dystonia with an alien limb phenomenon, cortical sensory findings, and limb apraxia. His premorbid diagnosis was cortical-basal ganglionic degeneration but he had the typical histologic features of a frontotemporal dementia of the MNDID subtype.