Ackman Jeanne B, Verzosa Stacey, Kovach Alexandra E, Louissaint Abner, Lanuti Michael, Wright Cameron D, Shepard Jo-Anne O, Halpern Elkan F
MGH Department of Radiology, Division of Thoracic Imaging and Intervention, Founders House 202, 55 Fruit Street, Boston, MA 02114, United States.
Massachusetts General Hospital, Harvard Medical School, United States.
Eur J Radiol. 2015 Mar;84(3):524-533. doi: 10.1016/j.ejrad.2014.11.042. Epub 2014 Dec 13.
To determine the non-therapeutic thymectomy rate in a recent six-year consecutive thymectomy cohort, the etiology of these unnecessary thymectomies, and the differentiating CT features of thymoma, lymphoma, thymic hyperplasia, and thymic cysts.
Electronic data base query of all thymectomies performed at the Massachusetts General Hospital from 2006 to 2012 yielded 160 thymectomy cases, 124 of which had available imaging. The non-therapeutic thymectomy rate (includes thymectomy for lymphoma and benign disease) was calculated. Preoperative clinical and CT imaging features were assessed by review of the in-house electronic medical record by 2 thoracic surgeons and 2 pathology-blinded radiologists, respectively.
The non-therapeutic thymectomy rate of 43.8% (70/160) was largely secondary to concern for thymoma and was comprised of lymphoma (54.3%, 38/70), thymic bed cysts (24.3%, 17/70), thymic hyperplasia (17.1%, 12/70), and reactive or atrophic tissue (4.3%, 3/70). Among these four lesions, there were significant differences in location with respect to midline, morphology, circumscription, homogeneity of attenuation, fatty intercalation, coexistent lymphadenopathy, overt pericardial invasion, and mass effect (p<0.001). True thymic cysts ranged in attenuation from -20 to 58Hounsfield units (HU), with a mean attenuation of 23HU.
The high rate of unnecessary thymectomy was due to misinterpretation of thymic cysts, thymic hyperplasia, and lymphoma as thymoma on chest CT. This study demonstrates differentiating features between thymoma, lymphoma, thymic hyperplasia, and thymic cysts on chest CT which may help triage more patients away from thymectomy toward less invasive and non-invasive means of diagnosis and thereby lower the non-therapeutic thymectomy rate.
确定在一个最近连续六年的胸腺切除术队列中的非治疗性胸腺切除术发生率、这些不必要胸腺切除术的病因，以及胸腺瘤、淋巴瘤、胸腺增生和胸腺囊肿的鉴别CT特征。
对2006年至2012年在马萨诸塞州总医院进行的所有胸腺切除术进行电子数据库查询，得到160例胸腺切除术病例，其中124例有可用的影像学资料。计算非治疗性胸腺切除术发生率（包括因淋巴瘤和良性疾病进行的胸腺切除术）。分别由2名胸外科医生和2名不知病理结果的放射科医生通过查阅内部电子病历评估术前临床和CT影像特征。
非治疗性胸腺切除术发生率为43.8%（70/160），主要是由于对胸腺瘤的担忧，包括淋巴瘤（54.3%，38/70）、胸腺床囊肿（24.3%，17/70）、胸腺增生（17.1%，12/70）以及反应性或萎缩性组织（4.3%，3/70）。在这四种病变中，在相对于中线的位置、形态、边界、衰减均匀性、脂肪嵌入、并存淋巴结病、明显的心包侵犯和肿块效应方面存在显著差异（p<0.001）。真正的胸腺囊肿衰减范围为-20至58亨氏单位（HU），平均衰减为23HU。
不必要胸腺切除术的高发生率是由于在胸部CT上把胸腺囊肿、胸腺增生和淋巴瘤误判为胸腺瘤。本研究展示了胸腺瘤、淋巴瘤、胸腺增生和胸腺囊肿在胸部CT上的鉴别特征，这可能有助于将更多患者从胸腺切除术转向侵入性较小和非侵入性的诊断方法，从而降低非治疗性胸腺切除术发生率。
