Dissociated motor loss syndrome with cavities in the anterior horns.

A 74-year-old man developed proximal muscular weakness and wasting of the left upper extremity without sensory disturbance or myelopathic symptoms. The muscle atrophy had not progressed for a few years. Radiological examination of the spine showed cervical disc herniation. These findings and electrophysiological studies excluded motor neuron diseases, permitting the diagnosis of dissociated motor loss syndrome. Interestingly, delayed computerized tomographic myelography disclosed cavities in the anterior horns of the spinal cord, which coincided with the clinical symptoms. Previous radiological and pathological examinations showed formation of such cavities within the spinal cord resulting from chronic compression, which was followed by ischemic change. In this context, the present case supports ischemia as a cause of dissociated motor loss syndrome.