A Case of Anti-signal Recognition Particle Antibody-associated Myopathy with a Dermatomyositis-like Rash Successfully Treated for Concomitant Cardiac Involvement with Intravenous Immunoglobulin Therapy

Anti-signal recognition particle (SRP) myopathy has recently been regarded as immune-mediated necrotizing myopathy (IMNM). Anti-SRP myopathy primarily presents with muscle symptoms, but it can also involve extramuscular symptoms, among which cardiac disease can be fatal. Despite its potentially severe course, anti-SRP myopathy often resists conventional immunosuppressive therapy. A 72-year-old woman diagnosed with anti-SRP myopathy developed cardiomyopathy and pericardial effusion. The disease could not be controlled with prednisolone (PSL) and tacrolimus (TAC), but an improvement was achieved with intensified therapy using intravenous immunoglobulin (IVIG). Early intensification of IVIG may therefore improve the patient prognosis.