Subclinical myasthenia gravis (MG) can usually be
found by the detection of the anti-acetylcholine receptor
(AChR) antibody following a roentgen diagnosis of thymoma.
We describe a rare case of latent MG diagnosed by
anti-AChR antibody positivity determined consequent to a
protracted postoperative non-depolarizing neuromuscular
blocking effect in a patient with no preoperative symptoms
of MG.