[A case of thymoma with an increased sensitivity to pancuronium].

It is well-known that anesthesia and surgery may precipitate muscle weakness in the patients with myasthenia gravis and some patient were not recognized as myasthenia until such episodes. A 74-year-old woman with increased sensitivity to pancuronium who, in spite of the very high titer of anti-acetylcholine receptor antibodies, showed no clinical manifestation of myasthenia gravis before operation. And computed tomographies revealed the presence of a thymoma in her anterior mediastinum. Although we have performed extended thymectomy, ptosis appeared 4 month after the operation. This patient might be called as "premyasthenic state" or "subclinical MG".