Myasthenia Gravis and Thymectomy at a Tertiary-Care Surgical Centre : A 20-Year Retrospective Review

Background: Myasthenia gravis (MG) is frequently associated with thymic abnormalities, including thymomas and hyperplasia. This study aims to analyze the clinical and pathological characteristics of thymectomized patients over a 20-year period, focusing on the relationship between thymoma subtype and MG incidence, as well as post-thymectomy remission outcomes. Methods: We retrospectively analyzed 420 patients who underwent thymectomy (open or VATS), with a mean age of 54.4 years and 59% female. Thymic pathology included thymomas (56.2%), thymic cysts (14.3%), and other lesions. 39.5% of patients had MG, of which 48.8% were thymomatous MG. Multivariate regression was used to identify predictors of MG and remission outcomes. Results: MG was significantly associated with younger age (p < 0.005), germinal hyperplasia (p < 0.001), and thymoma, especially WHO B2 subtype (p = 0.016). Six-month complete remission rates did not differ between thymomatous and non-thymomatous MG. In the subgroup undergoing VATS, median length of stay decreased to 3 days compared to 5 days in the overall cohort. The intraoperative complication rate for VATS was 1.5%, compared to 11.6% for open surgery. Conclusions: This is one of the largest single-center studies to evaluate the link between thymoma histology and MG. WHO type B2 thymoma and germinal hyperplasia were more commonly associated with MG. Comparable remission outcomes support the role of thymectomy in both thymomatous and non-thymomatous MG, emphasizing the need for individualized surgical strategies.