Dermatomyositis-like muscle pathology in patients with chronic graft-versus-host disease.

Myositis is a rare complication of chronic graft-versus-host disease (cGVHD) following hematopoietic stem cell transplantation (HSCT). Almost all such patients have been reported to have polymyositis (PM). We describe clinical, pathologic, and molecular studies of 3 patients with cGVHD following allogeneic HSCT who developed myopathy. In each case, perifascicular atrophy, the pathognomonic histologic feature of dermatomyositis (DM), was observed.