Dermatomyositis with inclusion body myositis pathology.

The pathogenic role of inflammation in inclusion body myositis (IBM) remains uncertain. A 63-year-old man developed a severe, rapidly progressive myopathy with clinical features typical of dermatomyositis (DM), but muscle pathology was typical of IBM. Treatment with prednisone and methotrexate resulted in complete remission of symptoms. Together with two similar cases reported previously, this case suggests that the inflammatory process of DM may trigger the pathologic changes of IBM.