When one mythological being transforms into another

Abstract

BACKGROUNDAdvances in knowledge about immune-mediated myopathies (IIMs) demonstrate that many patients previously classified as having polymyositis (PM) could have an alternative diagnosis. The differential diagnosis for a suspected case of PM includes muscular dystrophies, metabolic, congenital or infectious myopathies, lower motor neuron disease and myasthenia gravis.