De Novo Myasthenia Gravis Induced by Atezolizumab in a Patient with Urothelial Carcinoma

The programmed cell death ligand-1 antibody, atezolizumab, is an immune checkpoint inhibitor approved for the treatment of various cancers. Herein, we describe a case of an 87-year-old man with advanced urothelial carcinoma. After surgery, atezolizumab was given. Subsequently, he developed generalized myasthenia gravis (MG) with elevated creatinine kinase and positive anti-striated muscle antibody. Although intravenous immunoglobulin was started, the patient developed cardiac arrhythmia and arrest. Our case not only reported MG as an immune-related adverse event of atezolizumab but also emphasized the significance of the programmed cell death-1 pathway in the pathogenesis of MG.