Extrapyramidal system involvement in motor neuron disease.

Three cases of motor neuron disease (MND), in which neuropathological findings were atypical, are reported. The first case manifested widespread and severe degeneration of the spinal cord, as in spinal fibrosis. Case 2 revealed severe degeneration of the pyramidal tract with many spheroids, which made it difficult to differentiate from primary amyotrophic lateral sclerosis. The last case revealed degeneration of the nigro-pallido-luysian system, even though no clinical manifestation of extrapyramidal and/or cerebellar symptoms had been noted throughout the clinical course. In MND, degeneration might occur in various locations other than the motor system.