Myopathology of non-infectious inflammatory myopathies - the current status.

Besides the classical inflammatory myopathies (IM), dermatomyositis (DM), polymyositis, and inclusion body myositis, the much larger spectrum of IM includes focal and nodular myositis, granulomatous myositis, macrophagic myofasciitis, graft vs. host myositis, eosinophilic myositis, and other immune-associated conditions, some of them only recently described. In addition, paraneoplastic, statin-induced and critical illness myopathies have been considered immune-associated IM. Infectious, i.e., bacterial, viral, and parasitic IM are much less frequent in the northern hemisphere. In IM, muscle biopsy is an essential diagnostic procedure to initiate therapy. The myopathological spectrum encompa…