Thymoma is associated with relapse of symptoms after transsternal thymectomy for myasthenia gravis.

Thymectomy is considered a therapeutic option for patients with myasthenia gravis. A myasthenic patient who has not received any treatment for years and shows no signs or symptoms of the disease after operation is still susceptible to a recurrence of myasthenic symptoms. To investigate which factors are related to relapse of symptoms in patients having thymectomy, we conduct a retrospective review in the patients who had experienced complete remission after thymectomy. Complete remission was achieved in 92 of 154 patients who received extended transsternal thymectomy for myasthenia gravis. Among these 92 patients, 20 patients had relapse of symptoms and needed medication again after complete remission was achieved (21.7%). Ten of 22 patients in the thymomatous group had relapse of symptom after complete remission was achieved, while only 10 of 70 patients in the nonthymomatous group had relapse of symptom (P=0.006). Multivariate Cox regression analysis revealed that thymoma was an independent factor for the development of relapse of symptoms. In conclusion, thymoma is an adverse prognostic factor for the MG patients who have experienced complete remission after thymectomy. The patients with thymoma had a greater possibility to develop relapse of symptoms than the patients without thymoma.