Anti-Mi2 dermatomyositis revisited: pure DM phenotype with muscle fiber necrosis and high risk of malignancy

Abstract : Anti-Mi2 are dermatomyositis-specific autoantibodies (Aabs) that have been associated, in small cohorts, with a good prognosis possibly related to a lower malignancy risk. Our objective was to describe the phenotype of anti-Mi-2 dermatomyositis (DM) in a larger cohort. A national multicenter retrospective cohort study was performed including all patients with a clinical phenotype suggestive of DM (cutaneous manifestations and/or muscle involvement) and a positive anti-Mi2 Aabs. Medical records were retrospectively reviewed to assess clinical and histological features, and presence of cancer occurring ± 3 years of diagnosing myositis (CAM).