Objective To investigate the treatments and prognostic factors of myasthenia gravis (MG) accompanied with thymomas and evaluate the treatment effects of such cases. Methods Our study was based on 103 cases of MG with surgically proved thymoma treated in our hospital The patients were treated with steroid therapy, radiotherapy and chemotherapy We evaluated the long term effects, the survival rate and the prognostic factors. Results The overall effective rate was 78 6%.Twenty three patients obtained a result of complete remission (22 3%), 26 pharmacological remission (25 2%), and 32 improvement (31 1%) The overall survival rates were 77 8% and 48 5% at 5 and 10 years, respectively Based on the three histologic types, the survival rates at 5 and 10 years of lymphyocytic thymoma were 88 9% and 72 7% respectively, of mixed thymoma 83 3% and 58 3%, of epithelial thymoma 55 6% and 10 0% The survival rates of stage Ⅰ and Ⅱ were 89 8% and 76 2% respectively at 5 and 10 years, and of stage Ⅲ and Ⅳ were 35 7% and 0% The survival rates of patients treated with steroid and radiotherapy were 88 9% and 57 1% respectively. Conclusions The administration of steroids therapy, radiotherapy and chemotherapy after removal of thymomas may enhance the long term curative effect in patients of MG with thymoma However, patients with epithelial thymoma or Masaoka's stage Ⅲ and Ⅳ had rather poor prognosis

Thymus has an important significance to the pathogenesis and treatment for myasthenia gravis (MG). Thymoma accounts for 10 to 15% in the MG patients, which is short of localized damage feature so as to make misdiagnosis usually. Using citric acid extracted sacrolemma protein antigen from human skeletal muscle, CAE-Abs in the sera of 103 MG patients were detected by indirect hemoagglutination assay (IHA) and the positive rate was 78.9% (cases of 15/19); and then the CAE-Abs in the sera of 123 MG patients were detected by ELISA and the positive rate'was 82.6% (cases of 19/23). But the positive rate of CAE-Ab in the sera of MG without thymoma was only 0-4.0% (cases of 3/77). This results indicate that CAE-Ab has significant correlativity for MG with thymoma.