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Background:Thymoma is originated from the thymic epithelium. It is potentially malignant and can be accompanied by various complications. The most common complication was myasthenia gravis(MG) and it is often associated with some paraneoplastic syndromes. Like any tumors, adopting TNM staging system for thymoma is still controversial, because it is rarely metastasize to lymph nodes and other organs. Treatment of thymoma are various, only thymectomy is enough for benign thymomas, but for invasive thymoma, it usually depends on the surgeon’s desire. Treatment options for myasthenic thymoma is more complicated. In this study, we statistically analyzed 174 thymoma patients, presented current management options and role of surgery.Materials and Methods:We have retrospectively analysed thymoma patients who were surgically resected and histopathologically proved as thymoma between Jan.2003 and Dec.2010. We presented thymoma patients by adopting Masaoka staging system, WHO hispopathologic classofication and MGFA classification.SPSS 17.0 was used for statistical analysis. Results:Thymomas were classified according to WHO hispopathologic classofication, type A thymoma (18%), type AB 50 (28%), type B1 26 (15%), type B2 43 (25%), type B3 19 (11%), and type C 6(4%), benign to malignant ratio was 46:54. Thymomas were staged by Masaoka staging system, StageⅠ69 (39%), StageⅡA 33 (19%), StageⅡB 22 (13%),Ⅲ35 (19%), StageⅣA12 (8%) and StageⅣB 3 (2%). In our series, stageⅠandⅡwere more common than other stages. Among them,61 patients were myasthenic thymoma, we grouped them by MGFA classification system into 5 groups, ClassⅠ16 (26%), ClassⅡ28 (46%), Class in 17 (28%), Class IVand ClassⅤwere 0. Type B thymoma are more associated with MG, B2 is the most common type, accounted for 44% of all mysthenic thymoma.157(90%) thymoma patients had complete resection, and 17(10%). of them had incomplete resection. There were no surgery related deaths. We conducted postoperative follow-up for 131 patients,26 were died. Among them 9 were died because of the recurrence and MG,7 were died of cardiovascular events,3 were died of pulmonary infection,7 were died of unknowed reason. Patients were followed up by Masaoka staging system, the 5-year survival rates were 100% for StageⅠ,98% for StageⅡ,82% for StageⅢ,52% for Stage IV respectively. Result of Masaoka staging system evidence was statistically significant (X2=39.87, P<0.01). Patients were followed up by WHO pathologic classification system, the 5-year survival rates were 100% for type A,95% for type AB,84% for type B1,81% for type B2,79% for type B3 and 56% for type C respectively. Result of WHO pathologic classification system evidence was statistically significant (X2=0.98, P<0.05).Conclusion:1. In our study, benign to malignant ratio was 46:54, no significant differences.2. In our study, myasthenic thymoma accounts for 1/3 of all thymoma patients, major histopathological type is B2, most of them were generalized MG. There were no correlation between the severity of MG and thymoma histopathology.3. In our study, the main treatment option was surgery, there were no surgery related death, surgery is still the mainstay treatement for mysthenic and invasive thymoma, we achieved a satisfactory result for such patients.4. Thymoma Masaoka staging, WHO histopathology and the completeness of resection are important prognostic factors.
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