Kondo K, Monden Y.
Objective: A few thymoma patients without myasthenia gravis (MG) have been observed to develop MG after total removal of the thymoma (postoperative MG). However, the cause of this is not yet known because of the rarity of postoperative MG patients. This study evaluated the clinical characteristics of the 8 postoperative MG patients. Methods: We compiled 1089 thymoma patients treated between 1990 and 1994 in 115 institutes in Japan, and found 8 cases of postoperative MG. Results: Postoperative MG was found in 8 (0.97%) of 827 thymoma patients without preoperative MG. The postoperative MG patients included 1 male and 7 females, with a mean age of 50.5+/-15.0 years. The thymoma was completely resected in all cases. The surgical method used was extended thymectomy in 2 cases and thymothymectomy in 6 cases. There were 2 cases (0.7%) of postoperative MG in the extended thymectomy group (n=275), 6 (1.9%) in the thymothymectomy group (n=321), and none in the tumor resection group (n=137). The interval between thymectomy and the onset of postoperative MG varied (6 days-45 months, 19.3+/-16.5 months). The type of MG was ocular in 2 cases and general in 5 cases, according to the modified Osserman classification. The postoperative MG was responsive to anti-cholinesterase compounds and/or steroids. The improvement rate was 86%. Conclusions: Postoperative MG was present in about 1% of the patients who underwent total thymoma resection. Resection of the thymus gland does not prevent postoperative MG.
胸腺瘤术后出现的重症肌无力
少数没有重症肌无力的胸腺瘤病人在手术后可出现MG，即所谓术后MG。由于病例不多，有关术后出现MG的机制尚不明确。Kondo等评估了827名术前无MG的胸腺瘤切除病人，发现还有8名术后出现MG，占0.97%。其中女性7例，男性1例，平均年龄50.5+/-15。所有病人均进行完全胸腺切除。切除距MG发病时间为6天至45个月，平均19.3+/-16.5月。2例为眼肌型，5例为全身型。均对胆碱酯酶抑制剂和或激素反应良好，症状缓解率为86%。作者认为全胸腺瘤切除病人中约有1%会发生术后MG，胸腺切除并不能防止术后MG。
Eur J Cardiothorac Surg. 2005 May 31; [Epub ahead of print]
