Skeletal muscle abnormalities in two patients with dystonia

We report two patients with dystonia aged 53 and 27 years. One patient was diagnosed as a sporadic case of primary dystonia. The other patient was diagnosed as having secondary dystonia following head injury. Skeletal muscle specimens were obtained by open biopsy from the two patients. The muscle biopsy specimens showed lobulated fibers, ring fibers, and type 1 fiber atrophy. Dystonia comprises involuntary movement and causes abnormal muscle tone. We considered that the abnormal muscle tone caused by dystonia might be involved in the pathogenesis of these histochemical changes in skeletal muscle.