The Mythology of Polymyositis.

Polymyositis (PM) has been in the diagnostic armamentarium in medicine since the mid-nineteenth century. Medicine training puts a heavy emphasis on this diagnosis, and anyone with proximal muscle weakness with elevated serum creatinine kinase is assumed to be PM and a number of patients were rendered this diagnosis without additional testing. This article addresses the historical aspects of the diagnosis of PM and its evolution. We review this literature that addresses the rarity of this diagnosis and rightly puts in perspective in terms of its occurrence in relation to other inflammatory myositides.