Inflammatory myopathy refers to a group of closely related, muscle-specific auto-immune diseases. The most important inflammatory myopathy is polyomyositis. In this picture, you can see a wide variation in myofiber size. There is prominent lymphohistiocytic infiltrates and many muscles undergo myophagocytosis.

Polymyositis may be associated with a skin rash as dermatomyositis or associated with other systemic auto-immune diseases.