Sporadic motor neuron disease with Lewy body-like hyaline inclusions.

Lewy body-like hyaline inclusions were immunocytochemically and electron microscopically investigated in a patient with sporadic motor neuron disease. The hyaline inclusions were chiefly observed within the perikarya of both normal-looking and chromatolytic anterior horn cells in the lumbar spinal cord, but some were detected in the axons and dendrites. Usually, a single inclusion was found in the perikaryon, but in rare cases two or more were observed. Immunocytochemically, these inclusions were intensely immunostained with anti-ubiquitin antibody. Ultrastructurally, the hyaline inclusions were chiefly composed of randomly arranged linear structures associated with ribosome-like granules, varying from compactly arranged linear densities to more loosely packed ones. They contained scattered vesicles of various sizes and occasionally a focal accumulation of randomly arranged 10-nm neurofilaments or 13-25-nm filamentous structures.