Spinocerebellar degeneration with prominent involvement of the motor neuron system: autopsy report of a sporadic case.

A sporadic case of spinocerebellar degeneration with prominent involvement of the motor neuron system is reported. A Japanese male without contributing family history, developed cerebellar ataxia at the age of 52, followed by generalized amyotrophy and ophthalmoplegia, and died aged 58. The clinical findings were pathologically verified as degeneration of the spino-ponto-cerebellar system and the motor neuron system, the latter almost identical to those of amyotrophic lateral sclerosis. Additional subclinical changes were found in the dentate nucleus and substantia nigra. Brain-stem nuclei subserving eye movements were well preserved, suggesting a supranuclear basis for the ophthalmoplegia. This unusual combination of system degenerations has on rare occasions been reported in the heredofamilial cerebellar disorders. As a sporadic case, however, this may be the first autopsy case of spinocerebellar degeneration with severe concurrent involvement of the motor neuron system.