Dysimmunes and inflammatory myopathies (DIM) are divided in four groups, on the grounds of clinical and histopathological criteria: dermatomyositis, polymyositis, inclusion body myositis and autoimmune necrotizing myopathy. They may present as unique condition (primary DIM), or in association with cancer (paraneoplastic DIM) or connective tissue disease (overlap syndrome). All of them but inclusion body myositis usually respond to immunomodulatory therapy, including steroids, immunosuppressive drugs, and intravenous immunglobulins. However, most often they are chronic diseases with relapses and therapeutic failure.