Introduction

Myasthenia gravis (MG) Lambert-Eaton (LE) overlap syndrome is a rare condition. Here, we describe the first case of MG-LE overlap syndrome revealed by the anti-programmed cell death 1 inhibitor, nivolumab, in a patient treated for metastatic melanoma.

Case

Three months after receiving nivolumab and 1 month after brain metastasis radiotherapy, our patient developed generalized fatigue with intermittent ptosis and swallowing difficulty suggesting a myasthenic syndrome. Electromyogram findings, anti-acetylcholine receptor, and anti-calcium channel antibodies levels were consistent with an immune-related myasthenic syndrome with specific features for both MG and LE syndromes. Immunotherapy with nivolumab was stopped. Patient was treated with systemic immunosuppressive and anti-cholinesterase drugs, with remarkable improvement of his neurological symptoms. Prolonged partial remission was obtained for his metastatic melanoma without need for a third-line treatment. Two years later, a relapse of hismyasthenic symptoms was observed along with new neurological symptoms related to brain radiation necrosis.

Conclusion

We describe the first case of MG-LE overlap syndrome diagnosed after anti-PD1 immunotherapy for metastatic melanoma, which appeared after radiation therapy and then relapsed after brain radiation necrosis. We hypothesized a role for brain inflammation as a trigger for MG-LE onset. Neuro-muscular junctions disease induced or revealed by checkpoint inhibitors can be challenging and requires long-term follow-up.

中文翻译：

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纳武单抗在转移性黑色素瘤患者中诱发的重症肌无力 Lambert-Eaton 重叠综合征

介绍

重症肌无力 (MG) Lambert-Eaton (LE) 重叠综合征是一种罕见的疾病。在这里，我们描述了第一例由抗程序性细胞死亡 1 抑制剂纳武单抗在接受转移性黑色素瘤治疗的患者中发现的 MG-LE 重叠综合征病例。

案件

接受纳武单抗 3 个月后和脑转移放疗 1 个月后，我们的患者出现全身乏力、间歇性上睑下垂和吞咽困难，提示肌无力综合征。肌电图结果、抗乙酰胆碱受体和抗钙通道抗体水平与免疫相关肌无力综合征一致，具有 MG 和 LE 综合征的特定特征。停止使用纳武单抗进行免疫治疗。患者接受全身免疫抑制和抗胆碱酯酶药物治疗，神经症状明显改善。他的转移性黑色素瘤获得了延长的部分缓解，无需三线治疗。两年后，观察到肌无力症状复发以及与脑辐射坏死相关的新神经系统症状。

结论

我们描述了在针对转移性黑色素瘤的抗 PD1 免疫治疗后诊断出的第一例 MG-LE 重叠综合征病例，该病例在放射治疗后出现，然后在脑放射坏死后复发。我们假设脑炎症是 MG-LE 发病的诱因。检查点抑制剂诱发或揭示的神经肌肉接头疾病可能具有挑战性，需要长期随访。