Long-term clinical outcome after extended thymectomy combined postoperative high-dose steroid therapy for juvenile myasthenia gravis.

Myasthenia gravis (MG) is considered to be an autoimmune disorder of neuromuscular transmission and is rare in childhood. We report 3 juvenile MG (JMG) cases of extended thymectomy (ETMX) combined postoperative high-dose steroid therapy. All patients developed MG symptoms under the age of 14 years and were given cholinergic drugs and had generalized MG: the Myasthenia Gravis Foundation of America classification II was present in 1 case and classification III was in 2. All patients were taking pyridostigmine before surgery; none was treated with prednisone preoperatively. All patients performed the ETMX combined postoperative high-dose steroid therapy. Muscle weakness of extremities and bulbar symptoms improved in all patients, but not all exhibited an unstable phase in their clinical course as a result of combined therapy. There was no postoperative morbidity or mortality. All patients had follicular lymphoid hyperplasia without thymoma. Follow-up for more than 5 years has shown one to be in complete remission and the others to have improved symptoms. Although our results are inconclusive because we used only a few JMG patients, the ETMX combined postoperative high-dose steroid therapy appeared to provide a better chance of remission or control of symptoms.