A Contemporaneous Onset of Eosinophilic Granulomatosis with Polyangiitis and Myasthenia Gravis.

Autoimmune neuromuscular disorders in patients with eosinophilic granulomatosis with polyangiitis (EGPA) are relatively uncommon. Although two cases of myasthenia gravis (MG) comorbid with EGPA have been reported, both patients developed EGPA several years after starting immunosuppressive treatment for MG. We herein report a 75-year-old man with a rare co-occurrence of EGPA and MG that developed simultaneously and was successfully treated with immunosuppressive therapy. Distinguishing the neurological symptoms of EGPA from complications of other neurological autoimmune diseases, such as MG, is crucial, especially in patients with eosinophilia.