Motor neuron disease with dementia combined with degeneration of striatonigral and pallidoluysian systems

This study concerns an autopsy case of motor neuron disease with dementia (MND-D) that exhibited unusual clinical and neuropathological findings, The patient was a Japanese man without any relevant family history who was 60 years old at the time of death. His clinical manifestation included character change at the age of 54, followed by frozen gait, dysarthria and bradykinesia and he was diagnosed with Parkinson's disease. He gradually developed spastic paresis and died of respiratory failure 6 years after onset of the illness. Neuropathological examinations showed prominent degeneration in the striatonigral and pallidoluysian systems in addition to the neuronal loss and microvacuolation in the second to third layers of the frontal and temporal cortex, the involvement of the upper and lower motor neuron systems and the presence of ubiquitinated neuronal inclusions. To our knowledge, five cases of motor neuron disease (MND) combined with pallido-nigro-luysian atrophy (PNLA) have been reported previously, but the present case is the first report of MND-D combined with the degeneration of the striatonigral and pallidoluysian systems. Such an association may represent more than a coincidental occurrence, and it suggests that MND-D is not simply a disease of the motor neuron system but a multisystem degeneration.