Polymyositis as a manifestation of chronic graft-versus-host disease

A syndrome indistinguishable from idiopathic polymyositis occurred in 11 patients as a manifestation of chronic GVHD. All patients had elevation of creatine phosphokinase (CPK). Immunohistology demonstrated the effector cells in the muscle infiltrates as cytotoxic T cells, a finding similar to idiopathic polymyositis. Polymyositis is a rarely reported complication of chronic graft-versus-host disease (GVHD) with only 8 cases described in the literature. We encountered this syndrome in a small but significant percentage of our patients with chronic GVHD. Polymyositis associated with chronic GVHD does not affect the overall prognosis for the patient. Moreover, polymyositis can be the only manifestation of chronic GVHD. Awareness of this complication is important because it can be confused with other causes of muscle weakness after bone marrow transplantation. Finally, prompt initiation of corticosteroid therapy results in a rapid improvement of the associated symptoms.