[A meta-analysis of thymoma-associated systemic lupus erythematosus from 1975 - 2008 worldwide]

To investigate the clinical features and treatment strategy for the thymoma-associated systemic lupus erythematosus (SLE) in a worldwide perspective.

All articles between 1975 to 2008 were searched with the key words "SLE Thymoma" or "SLE thymectomy" in the database of Pubmed & Medline; the Chinese articles were searched with the same key words in the database of China Hospital Knowledge Database (CHKD). Data were extracted and analyzed.

44 patients from 24 studies were available for this analysis with a male-to-female ratio of 1: 6. The mean age of SLE onset was 47.9 (21-76) while the mean age of discovery of thymoma was 48.5 (18-77). The clinical picture of SLE was classical with no statistical difference between genders. However, the thymoma-associated SLE occurs in patients older than the classical onset age of SLE (P < 0.01). As for treatment, the glucocorticoids-based immune-suppressive therapy still proves to be effective (P < 0.01). The thymoma could be benign or invasive which does not depend on gender or age. There is no statistical difference with regards to pathologic sub-types. As for the patients who already had SLE when discovering the thymoma, the clinical outcomes varied after the thymectomy (remission 27.8%, exacerbation 33.3%, no change 38.9%, P > 0.05).

The possibility of thymoma should be considered among those late-onset SLE patients. The glucocorticoid-based immunosuppressive therapy is effective for thymoma-associated SLE. To treat SLE is not an indication for thymectomy.