Asymptomatic myasthenia gravis manifested after removal of mediastinal tumors. Report of two cases.

Asymptomatic myasthenia gravis firstly manifested as total paralysis in patients submitted to a surgical procedure should be considered extremely rare. Two cases of latent myasthenia gravis manifested after thoracotomy for removal of mediastinal tumor are reported. Prolonged apnoea and need for postoperative mechanical support of respiration was most likely due to non-depolarizing relaxants administration. In both cases edrophonium test was positive and the histology of the tumor showed thymoma. The further recovery after pyridostigmine treatment was uneventful for both patients.