Myasthenia gravis (MG) is an autoimmune disease in which autoantibodies against the nicotinic acetylcholine receptor (AChR) at the neuromuscular junction (NMJ) cause impaired neuromuscular transmission. The patient was a 64-year-old man with a history of thymectomy who underwent a partial glossectomy 14 months ago, with the chief complaints of dysarthria and dysphagia. We initially suspected tumor recurrence or brain metastasis. But he showed blepharoptosis, and we suspected MG thus performed an examination. Diagnostic tests (edrophonium test and ice test) and a laboratory test (serum anti-ACh receptor antibody titer) were performed at our hospital. Both diagnostic tests returned positive for MG, and the serum anti-ACh receptor antibody titer was 34.0 nmol/L. Based on these results, the patient was diagnosed with post-thymectomy myasthenia gravis (PTMG). His symptoms improved after prescription of prednisolone (corticosteroid) and pyridostigmine bromide (cholinesterase antagonist).
