Miyoshi R, Yamaji Y, Shima S, Fujita J, Okada H, Takahara J
First Department of Internal Medicine, Kagawa Medical School.
Nihon Kyobu Shikkan Gakkai Zasshi. 1995 Apr;33(4):456-62.
A 56-year-old man had been complaining of progressive proximal muscle weakness and bilateral ptosis before his first admission to our hospital. He received an injection of edrophonium chloride, which resulted in remarkable improvement of muscle strength. Electromyographic studies revealed a compound muscle action potential that decreased after repetitive stimulation at a high rate (15 Hz). He was regarded as having myasthenia gravis (MG) rather than Eaton-Lambert syndrome because of these findings. Eighteen months after successful treatment of MG with oral anticholinesterase medication, he complained of an abdominal mass. The mass was found to be a tumor that had metastasized from a primary small cell carcinoma of the lung. Cases of MG with small cell carcinoma of the lung seem to be very rare, and the details of the relationship between them remain unknown. In this patient, MG may have developed by paraneoplastic mechanisms. This hypothesis is interesting, since it has been demonstrated recently by molecular biological techniques that small cell carcinomas of the lung express nicotinic acetylcholine receptors.
一名56岁男性在首次入院前一直抱怨进行性近端肌无力和双侧上睑下垂。他接受了氯化依酚氯铵注射，肌力得到显著改善。肌电图研究显示，在高频（15Hz）重复刺激后复合肌肉动作电位降低。基于这些发现，他被诊断为重症肌无力（MG）而非伊顿-兰伯特综合征。在用口服抗胆碱酯酶药物成功治疗MG 18个月后，他主诉腹部有肿块。发现该肿块是一个从原发性肺小细胞癌转移而来的肿瘤。MG合并肺小细胞癌的病例似乎非常罕见，它们之间关系的细节仍不清楚。在该患者中，MG可能是通过副肿瘤机制发展而来。这个假设很有意思，因为最近通过分子生物学技术已证实肺小细胞癌表达烟碱型乙酰胆碱受体。
