Thymolipoma as a Rare Cause of Myasthenia Gravis

We present two cases of a rare thymic tumor presenting with ocular myasthenia gravis. Patient A was a male in his 40s who presented with bilateral diplopia. Investigations revealed negative myasthenic antibodies and positive jitter on single fiber electromyography. Patient B was a female in her 20s who presented with bilateral and fluctuating ptosis and diplopia, and was found to have positive acetylcholine receptor antibodies. Both patients demonstrated thymic hyperplasia on computed tomography chest and underwent robotic thymectomy. Pathology of the excised thymic tissue confirmed thymolipoma. We discuss the incidence, presentation, and management of thymolipomatous myasthenia gravis and present robotic thymectomy as a minimally invasive surgical treatment for thymolipoma.本研究报道2例以眼型重症肌无力（ocular myasthenia gravis）为首发表现的罕见胸腺肿瘤病例。病例A为40余岁男性，因双眼复视就诊；检查结果显示重症肌无力相关抗体呈阴性，单纤维肌电图（single fiber electromyography）检测可见肌纤维颤抖阳性。病例B为20余岁女性，表现为双侧波动性上睑下垂及复视，乙酰胆碱受体抗体检测呈阳性。两名患者的胸部计算机断层扫描（computed tomography）均提示胸腺增生，随后接受了机器人胸腺切除术。术后切除的胸腺组织病理学检查证实为胸腺脂肪瘤。本文就胸腺脂肪瘤相关性重症肌无力的发病率、临床表现及治疗方案展开讨论，并介绍机器人胸腺切除术作为胸腺脂肪瘤的微创外科治疗手段。