[A case of isolated neck extensor myopathy with parkinsonism].

We report an 84-year-old man with marked dropped head from 80 years of age. On neurologic examination, weakness was restricted to the neck extensor muscle, and the range of motility (ROM) of cervical spine was limited. He also had vascular parkinsonism. Needle electromyography indicated myogenic changes localized in the cervical paraspinal and trapezius muscles. CT and MRI of the cervical region demonstrated neck extensor muscle atrophy. Cervical paraspinal muscle biopsy revealed decreased numbers of muscle fibers which were embedded in markedly increased connective tissue. There was neither cellular infiltration nor specific changes. These findings were identical to those seen in isolated neck extensor myopathy recently proposed by Katz et al. (1996). In addition, pathological finding of the biceps muscle of the left arm suggested subclinical general myopathy because of mild fiber-size variability with moth-eaten appearance on NADH-TR straining. Neck extensor muscle weakness and limitation of ROM improved by physical therapy, and gait disturbance also improved simultaneously. To our knowledge, this is the first report isolated neck extensor myopathy in Japanese.