Polymyositis--an unusual manifestation of chronic graft-versus-host disease.

Polymyositis is a rare autoimmune manifestation of chronic graft-versus-host disease (GVHD) characterized by muscle pain, weakness, and an increase in muscle-related enzymes that responds well to treatment with immunosuppressive agents such as steroids and cyclosporine. We describe a case in which polymyositis was the main manifestation of chronic GVHD that occurred 12 months after allogeneic bone marrow transplantation in a patient with acute lymphocytic leukemia (ALL). The polymyositis responded well to treatment with steroids and cyclosporine, with no relapse of symptoms on tapering of the medication.