Mineo Tommaso Claudio, Tamburrini Alessandro, Schillaci Orazio, Ambrogi Vincenzo
Department of Surgery and Experimental Medicine, Multidisciplinary Myasthenia Gravis Unit, Policlinico Tor Vergata University, Rome, Italy.
Postgraduate School of Thoracic Surgery, Tor Vergata University, Rome, Italy.
Semin Thorac Cardiovasc Surg. 2018 Summer;30(2):222-227. doi: 10.1053/j.semtcvs.2018.02.027. Epub 2018 Mar 6.
Patients with thymoma and without clinical or electromyographical myasthenic signs may occasionally develop myasthenia several years after thymectomy. Hereby, we investigated the predictors and the evolution of this peculiar disease. We performed a retrospective analysis in 104 consecutive patients who underwent thymectomy between 1987 and 2013 for thymoma without clinical or electromyographic signs of myasthenia gravis. Predictors of post-thymectomy onset of myasthenia gravis were investigated with univariate time-to-disease analysis. Evolution of myasthenia was analyzed with time-to-regression analysis. Eight patients developed late myasthenia gravis after a median period of 33 months from thymectomy. No significant correlation was found for age, gender, Masaoka's stage, and World Health Organization histology. Only high preoperative serum acetylcholine-receptor antibodies titer (>0.3 nmol/L) was significantly associated with post-thymectomy myasthenia gravis at univariate time-to-disease (P = 0.003) analysis. Positron emission tomography was always performed in high-titer patients, and increased metabolic activity was detected in 4 of these patients. Surgical treatment through redo-sternotomy or video-assisted thoracoscopy was performed in these last cases with a remission in all patients after 12, 24, 32 and 48 months, respectively. No patient under medical treatment has yet developed a complete remission. In our study the presence of preoperative high-level serum acetylcholine receptor antibodies was the only factor significantly associated with the development of post-thymectomy myasthenia gravis. The persistence of residual islet of ectopic thymic tissue was one of the causes of the onset of myasthenia and its surgical removal was successful.
患有胸腺瘤但无临床或肌电图显示的重症肌无力体征的患者，在胸腺切除术后数年偶尔会出现重症肌无力。在此，我们研究了这种特殊疾病的预测因素及其演变情况。我们对1987年至2013年间连续接受胸腺切除术的104例胸腺瘤患者进行了回顾性分析，这些患者术前无重症肌无力的临床或肌电图表现。采用单变量疾病发生时间分析方法研究胸腺切除术后重症肌无力发病的预测因素。用回归时间分析方法分析重症肌无力的演变情况。8例患者在胸腺切除术后中位时间33个月后出现迟发性重症肌无力。年龄、性别、马萨oka分期和世界卫生组织组织学类型之间未发现显著相关性。在单变量疾病发生时间分析中，仅术前血清乙酰胆碱受体抗体滴度高（>0.3 nmol/L）与胸腺切除术后重症肌无力显著相关（P = 0.003）。对高滴度患者均进行了正电子发射断层扫描，其中4例患者检测到代谢活性增加。对这些患者最后采用了经再次胸骨切开术或电视辅助胸腔镜手术治疗，所有患者分别在12、24、32和48个月后病情缓解。接受药物治疗的患者均未完全缓解。在我们的研究中，术前高水平血清乙酰胆碱受体抗体的存在是与胸腺切除术后重症肌无力发生显著相关的唯一因素。残余异位胸腺组织小岛的持续存在是重症肌无力发病的原因之一，手术切除成功。
