NCIt definition : An umbrella term for diseases which have chronic muscle inflammation and weakness
of unknown etiology. The types of idiopathic inflammatory myopathy are further defined
by either clinicopathologic criteria or by the presence of certain autoantibodies.;
Alternative definition : NICHD: An umbrella term for diseases which have chronic muscle inflammation and weakness
of unknown etiology. The types of IIM are further defined by either clinicopathologic
criteria or by the presence of certain autoantibodies.;