Andrew L Mammen1. 1. 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.
Abstract
PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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.
PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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: Doris G Leung; Julie S Cohen; Elizabeth Harlan Michelle; Renkui Bai; Andrew L Mammen; Lisa Christopher-Stine Journal: J Clin Neuromuscul Dis Date: 2018-03