Division of Endocrinology, Department of Medicine, Georgetown University Hospital, Washington, DC 20010, USA.
Thyroid. 2010 Sep;20(9):1015-8. doi: 10.1089/thy.2009.0383.
Thymic hyperplasia is associated with Graves' disease, particularly in young patients. The degree of thymic transformation is minimal in most but not all patients. In the latter group radiological measurements of thyroid size and their change with treatment have rarely been reported. We present two patients with Graves' disease and relatively rapid resolution of thymic enlargement after successful treatment of their hyperthyroidism.
Three patients with thyrotoxicosis secondary to Graves' disease and marked thymic enlargement were seen at our institution during a 2-year period. On computed tomography (CT) studies their volumes were 67, 81, and 54 cm(3). Thymic hyperplasia in the setting of Graves' disease was the diagnosis of exclusion. Two of the patients returned for follow-up after successful treatment of thyrotoxicosis as requested. On repeat CT their thymic volumes had decreased by 72% and 78%, respectively. Two types of histological modifications of the thymus have been described in association with Graves' disease, namely, thymic parenchyma hyperplasia and medullary lymphoid hyperplasia. The mechanisms underlying thymic transformation in patients with Graves' hyperthyroidism are not completely elucidated, but autoimmune processes underlying Graves' disease are presumed to play a role. The clinical course of our patients is consistent with earlier literature, indicating that thymic enlargement may occur in conjunction with Graves' hyperthyroidism, and that it usually resolves as hyperthyroidism is treated, but there is little quantitative pre- and posttreatment of hyperthyroidism data.
Although every patient must be individually considered, it appears that thymic hyperplasia can be diagnosed in most Graves' hyperthyroid patients by considering the clinical context and appropriate radiologic studies such as CT. Raising awareness of the association of thymic hyperplasia in patients with Graves' hyperthyroidism and its resolution with the reversibility of the hyperthyroid state should prevent unnecessary thymic evaluation and surgery with its attendant risks.
胸腺增生与格雷夫斯病有关，尤其是在年轻患者中。但并非所有患者的胸腺转化程度都很小。在后一组中，很少有报道描述甲状腺大小的放射学测量及其随治疗的变化。我们介绍了两名患有格雷夫斯病的患者，他们的甲状腺功能亢进症在成功治疗后，胸腺肿大迅速消退。
在我们医院的 2 年期间，有 3 名因格雷夫斯病导致甲状腺功能亢进的患者出现明显的胸腺肿大。在计算机断层扫描（CT）研究中，他们的体积分别为 67、81 和 54 立方厘米。在格雷夫斯病中，胸腺增生是排除诊断。在成功治疗甲状腺功能亢进症后，有 2 名患者按要求回来进行随访。重复 CT 检查显示，他们的胸腺体积分别减少了 72%和 78%。与格雷夫斯病相关的胸腺有两种组织学改变，即胸腺实质增生和髓质淋巴样增生。格雷夫斯病患者胸腺转化的机制尚未完全阐明，但认为格雷夫斯病的自身免疫过程发挥了作用。我们患者的临床过程与早期文献一致，表明胸腺肿大可能与格雷夫斯病甲状腺功能亢进症同时发生，随着甲状腺功能亢进症的治疗，它通常会消退，但关于甲状腺功能亢进症的治疗前后的定量数据很少。
尽管必须考虑每个患者的个体情况，但似乎可以通过考虑临床背景和适当的影像学研究（如 CT）来诊断大多数格雷夫斯病甲状腺功能亢进症患者的胸腺增生。提高对格雷夫斯病甲状腺功能亢进症患者的胸腺增生及其与甲状腺功能亢进症的可逆性恢复的认识，应避免不必要的胸腺评估和手术及其相关风险。
