Nigral degeneration in a case of amyotrophic lateral sclerosis: evidence of Lewy body-like and skein-like inclusions in the pigmented neurons.

This report describes a 58-year-old man who exhibited the clinical features of amyotrophic lateral sclerosis (ALS) at autopsy, 1 year after clinical onset of the disease. Neuropathologically, in addition to degeneration of the upper and lower motor neurons, marked degeneration of the substantia nigra with the appearance of Lewy body-like inclusions (LBI) and skein-like inclusions (SLI) were observed in the remaining pigmented neurons. An immunohistochemical study revealed that both LBI and SLI were immunopositive for ubiquitin. Ultrastructurally, LBI in the substantia nigra were composed of randomly arranged 15 nm thick tubular structures associated with ribosome-like granules, similar to those of LBI in the lower motor neurons. SLI in the substantia nigra were composed of curved bundles of 5 nm thick filaments (thinner than those comprising the SLI in the lower motor neurons). We believe that degeneration of the substantia nigra could be one of the degenerative processes involved in ALS.