Introduction: Approximately 10% of patients with myasthenia gravis also have thymomas. The objective of this study was to describe the evolution after the thymectomy in 10 cases of myasthenia gravis associated with thymomas.
Methods: The study was based in a cohort of 132 patients with the diagnosis of myasthenia gravis, that underwent thymectomy between 1987 and 1997, and had at least three years of follow-up. We found 10 cases (7%) of thymomas. We analyzed the following variables: sex, age, associated diseases, disease evolution, Osserman, dose of edrophonium before surgery, steroid use before surgery, types of thymectomy, Osserman after surgery, pathology findings, and evolution. We used descriptive statistics according to the measurement level of the variables.
Results: Four (40%) were women and 6 (60%) were men. The antibodies against the acetylcholine receptor were tested in only 5 (50%) patients, and in all of them they were positive. 4 (40%) patients had complications after the thymectomy, being 2 (20%) of them myasthenic crisis, one (10%) pneumonia and another (10%) hemorrhage in the surgical wound. Six (60%) cases had malignant thymomas and 4 (40%) were benign. In the follow-up, 4 (40%) patients had a good clinical response of myasthenia gravis and 6 (60%) had no changes.
Conclusion: The response to thymectomy was not as good as the response of the vast majority of patients with myasthenia gravis without thymomas. We found a high frequency of malignant thymomas in our patients.