Ariad S, Geffen D B, Yanai-Inbar I, Zalmanov S, Piura B
Department of Oncology, Faculty of Health Sciences, Ben Gurion University of the Negev, Beer Sheva, Israel.
Gynecol Oncol. 1997 Mar;64(3):510-5. doi: 10.1006/gyno.1996.4553.
Myasthenia gravis is a neurologic disorder characterized by intermittent muscle weakness which improves after anticholinesterase medication. The pathogenesis of myasthenia gravis is associated with production of autoantibodies to nicotinic acetylcholine receptor in the motor end plate. Most patients do not have an underlying neoplasm, but in 10-15% of the cases, a thymoma may be detected. Apart from thymoma, no other tumor type or organ has consistently been associated with myasthenia gravis. We describe an unusual case of myasthenia gravis in a patient with malignant mixed Mullerian tumor of the uterine corpus. Initial histology revealed malignant mixed Mullerian tumor of a predominant carcinomatous element. At that time, there were no symptoms of muscle weakness. Intraabdominal metastases were detected later, concommitantly with symptoms of muscle weakness and the diagnosis of myasthenia gravis. Histology of the metastases disclosed an exclusive mesenchymal element with striated muscle differentiation. To the best of our knowledge this case is the first report of myasthenia gravis in a patient with malignant mixed Mullerian tumor of the uterine corpus. We propose that the mechanism contributing to myasthenia gravis in this patient was closely associated with the evolving histology and with the nature of the tumor, so that antibodies produced to muscle-like epitopes exposed by malignant cells could have cross-reacted with acetylcholine nicotinic receptors and caused myasthenia gravis.
重症肌无力是一种神经系统疾病，其特征为间歇性肌肉无力，抗胆碱酯酶药物治疗后症状可改善。重症肌无力的发病机制与运动终板中烟碱型乙酰胆碱受体自身抗体的产生有关。大多数患者无潜在肿瘤，但在10% - 15%的病例中可检测到胸腺瘤。除胸腺瘤外，没有其他肿瘤类型或器官一直与重症肌无力相关。我们描述了一例子宫体恶性混合苗勒管肿瘤患者发生重症肌无力的罕见病例。初始组织学检查显示以癌性成分占主导的恶性混合苗勒管肿瘤。当时无肌肉无力症状。后来发现腹腔内转移，同时出现肌肉无力症状并诊断为重症肌无力。转移灶的组织学检查显示为具有横纹肌分化的单纯间叶成分。据我们所知，该病例是子宫体恶性混合苗勒管肿瘤患者发生重症肌无力的首例报告。我们认为，该患者发生重症肌无力的机制与肿瘤不断演变的组织学特征及肿瘤性质密切相关，以至于针对恶性细胞暴露的肌肉样表位产生的抗体可能与乙酰胆碱烟碱型受体发生交叉反应，从而导致重症肌无力。
