Inclusion body myositis long after dermatomyositis: a report of two cases

Dermatomyositis, polymyositis, and inclusion body myositis are rare illnesses which appear to be distinct in clinical and pathologic features, pathogenesis, natural history, and response to therapy. We report two patients who first developed dermatomyositis, and then, after a disease-free interval of many years, developed inclusion body myositis. This may have useful therapeutic implications for patients with dermatomyositis whose illness bocomes refractory to treatment.