Adult-onset motor neuron disease with basophilic intraneuronal inclusion bodies.

A 53-year-old man initially displayed muscle atrophy and weakness and a slight degree of pyramidal signs, which became more prominent with time. Later, gaze palsy, autonomic dysfunction, and bedsore developed. The total clinical course was 63 months. Pathologically, there was loss of upper and lower motor neurons and other regions, as well as degeneration of the anterior and lateral funiculi of the spinal cord. Round or irregularly-shaped basophilic inclusions were found not only in the motor neurons, but also in other regions such as the putamen, globus pallidus, thalamus, subthalamic nucleus, red nucleus, midbrain tegmentum, pontine nucleus, dentate nucleus, inferior olivary nucleus and others. The inclusions consisted of randomly arranged 12-25 nm thick filaments studded with granules. This patient with adult onset of the disease exhibited features resembling those of "juvenile amyotrophic lateral sclerosis" with basophilic inclusions. Clinically as well as pathologically, the disease manifestations involved many systems other than the motor neurons.