role of thymectomy in patients with myasthenia gravis

ABSTRACT

Thymoma may be a negative prognostic factor with respect to the outcome of myasthenia gravis [MG]. Of 61 consecutive patients with MG undergoing thymectomy between January 1999 and January 2004, 19 had a thymoma. Postoperative radiation was administered to all patients with stage II thymoma and higher. To determine differences in presentation and outcome, thymoma patients were compared with patients with atrophic [n=34] or hyperplastic [n=27] thymus gland on final pathology. Thymoma patients were significantly older [52 +/- 14 vs 36 +/- 15 years, p <0.0001] and included a significantly higher proportion of males [54% vs 28%, p=0.006] than patients without thymoma. However, the preoperative Osserman grade and the duration of symptoms before surgery were not significantly different between groups. Mean follow-up after thymectomy was not significantly different between patients with or without thymoma [32 +/- 23 vs 37 +/- 19 months, respectively, p = 0.3]. At last follow-up, the proportion of asymptomatic patients [63% vs 70%, respectively, p= 0.5] and the mean Osserman grade [0.6 +/- 0.9 vs 0.5 +/- 0.9, respectively, p = 0.6] were similar in both groups. In addition, the rate of complete remission reached 36% at 5 years in patients with or without thymoma [p=0.8]. Although myasthenic patients with thymoma are significantly older and include a greater proportion of males, the overall outcome, including the rate of complete remission, was similar between patients with or without thymoma. Therefore, the presence of a thymoma should not necessarily be viewed as a negative prognostic factor regarding recovery from myasthenia gravis