title: Necrotizing myopathies: beyond statins.
abstract: OBJECTIVE
  This review discusses the spectrum of diseases associated with a necrotizing muscle biopsy. Although patients with toxic myopathies, endocrine dysfunction, and heritable myopathies may have prominent necrosis on muscle biopsy, immune-mediated myopathies are emphasized here.
  
  
  RESULTS
  A decade ago, immune-mediated necrotizing myopathy was recognized as a distinct form of myositis. Recent evidence now suggests that immune-mediated necrotizing myopathy is not one disease, but can be divided on the basis of the presence of distinct autoantibodies recognizing either the signal recognition particle or 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase. Anti-HMG-CoA reductase-positive patients can be further subdivided into those with and without statin exposure, the latter of which may be particularly refractory to immunosuppressive therapy.
  
  
  CONCLUSIONS
  A significant number of patients with autoimmune myopathy have a predominantly necrotizing muscle biopsy with minimal lymphocytic infiltration. This biopsy finding occurs in various forms myositis, including the antisynthetase syndrome, scleroderma-associated myopathy, antisignal recognition particle-associated myopathy, statin-associated anti-HMG-CoA reductase-positive autoimmune myopathy, and statin-naïve anti-HMG-CoA reductase-positive myopathy. Future progress in elucidating pathogenic mechanisms and defining optimal treatment strategies may depend upon recognizing these distinct forms of myositis and analyzing them as separate entities.
authors.affiliation: Muscle Disease Unit, Laboratory of Muscle Stem Cells and Gene Expression, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mammen
mesh_terms: D001327:Autoimmune Diseases / Q000276:immunology / Q000473:pathology*; D006801:Humans; D018482:Muscle, Skeletal / Q000276:immunology / Q000473:pathology*; D009135:Muscular Diseases / Q000276:immunology / Q000473:pathology*