Thymectomy in thymomatous and non-thymomatous myasthenia gravis: analysis of a cohort of 46 patients

Factors predicting remission after thymectomy for myasthenia gravis are not well known. To analyze the clinical evolution of the patients after this intervention and discuss about predictors of response. We retrospectively reviewed all clinical data of thymectomies in myasthenia gravis patients performed at our hospital between 2006 from 2016. Using the MGFA-PIS classification, «complete stable remission», «pharmacologic remission», «minimal manifestations» and «improved» were defined as «good clinical outcome», and «unchanged», «worse», «exacerbation» or «died», as «poor clinical outcome». In 46 consecutive thymectomies for myasthenia gravis, women comprised 71.7%. Median age was 37 years and 10.9% had concomitant autoimmune disorders associated. Thymoma (23.96%) was more frequent in older patients (53 ± 20 vs 33 ± 24 years) and men (54.5% vs 18.8%). A year after thymectomy, 28.2% of patients were in poor clinical outcome group and 54.3% had good clinical outcome. On univariate analysis, thymomatous myasthenia was associated with poor clinical outcome a year after surgical intervention. After ten years of follow-up, 9.8% reached complete stable remission, a total of 32 patients (78%) had a favourable outcome and thymoma was not correlated. Thymectomy is considered an effective treatment for myasthenia gravis but the benefit is not immediate. The presence of thymoma may determine a worse initial clinical response following thymectomy in patients with myasthenia gravis.