Lee Byung-Wan, Ihm Sung-Hee, Shin Ho-Seung, Yoo Hyung-Joon
Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Hallym University, Seoul, Korea.
Intern Med. 2008;47(11):1009-12. doi: 10.2169/internalmedicine.47.0838. Epub 2008 Jun 2.
Patients with thymoma are likely to present with associated autoimmunologic disorders. The occurrence of syndrome of inappropriate antidiuretic hormone (SIADH) attributable to thymoma is extremely rare. We herein present an extremely rare case of a 59-year-old man patient who was discovered to have malignant thymoma associated with myasthenia gravis, Graves' disease, and SIADH. He was admitted for evaluation and treatment of hyponatremia (Na 125 mEq/l). SIADH was diagnosed, and thymoma was identified as its cause. The patient was also found to have both Graves' disease and myasthenia gravis. The hyponatremia was normalized with water restriction and 3% saline therapy before thymectomy. The thymic tumor was a Masaoka stage III thymoma that resulted in direct invasion to the wall of the innominate vein, but there was no finding of invasion to other mediastinal organs. Complete thymectomy with innominate vein graft was performed. Microscopic histopathology findings corresponded to those of a mixed-type thymoma and type B2. However, immunohistochemical stain for antidiuretic hormone was negative in the tumor cells. Adjuvant radiation therapy was employed postoperatively, and the patient's postoperative recovery was uneventful. He subsequently reached a euthyroid state. And the reversal to normal sodium and osmolality levels was continued after the tumor removal without any further management for hyponatremia. The observation of this interesting case and a literature review provided us with the opportunity to explore the pathogenesis and clinical aspects of thymoma-related autoimmune and/or endocrine disorders which must be suspected in patients with thymoma.
胸腺瘤患者可能会伴有自身免疫性疾病。由胸腺瘤引起的抗利尿激素分泌异常综合征（SIADH）极为罕见。我们在此报告一例极为罕见的病例，一名59岁男性患者被发现患有恶性胸腺瘤，同时伴有重症肌无力、格雷夫斯病和SIADH。他因低钠血症（血钠125 mEq/l）入院接受评估和治疗。诊断为SIADH，病因确定为胸腺瘤。该患者还被发现患有格雷夫斯病和重症肌无力。在胸腺切除术前，通过限水和3%盐水治疗使低钠血症得到纠正。胸腺肿瘤为Masaoka III期胸腺瘤，已直接侵犯无名静脉壁，但未发现侵犯其他纵隔器官。实施了无名静脉移植的完整胸腺切除术。显微镜下组织病理学检查结果与混合型胸腺瘤和B2型相符。然而，肿瘤细胞中抗利尿激素的免疫组化染色为阴性。术后采用了辅助放疗，患者术后恢复顺利。随后他达到了甲状腺功能正常状态。肿瘤切除后血钠和渗透压水平持续恢复正常，无需对低钠血症进行进一步处理。对这一有趣病例的观察及文献回顾，为我们探索胸腺瘤相关自身免疫和/或内分泌紊乱的发病机制及临床情况提供了机会，而胸腺瘤患者必须怀疑存在这些紊乱。
