Non-hereditary Myopathies

Idiopathic inflammatory myopathies

3. Anti-synthetase syndrome-induced dysimmune myopathy

Anti-transfer RNA (tRNA) synthetase syndrome (ARS) is a disorder in which anti-aminoacyl-tRNA synthetase antibodies are associated with myositis along with manifestations of interstitial lung disease, arthropathy, Raynaud phenomenon, and systemic inflammatory symptoms including fever. Clinically, the myositis could be DM or PM. However, Stenzel (2015) and Mescam-Mancini (2015) reported that myositis in ARS syndrome differs from DM and PM, showing inflammation and degeneration of muscle fibers predominantly in the perifascicular area. It may be called perifascicular myositis or necrosis (Fig. 46). Intranuclear filamentous inclusions with actin were described by Stenzel (2015).

Fig.46
Anti aminoacyl –tRNA synthetase antibody associated myopathy shows inflammation in the perifascicular region, or perifascicular myositis (1). Many type 2C fibers are seen in the perifascicular region (2). CD4+T cells (3) and CD20+B cells (4) are frequently observed in the region.