Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
Department of Internal Medicine and Healthcare Research Institute, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Republic of Korea.
J Thorac Oncol. 2018 Mar;13(3):359-366. doi: 10.1016/j.jtho.2017.11.124. Epub 2017 Dec 9.
The aim of this study was to investigate the prevalence and characteristics of nodular lesions in the anterior mediastinum that had been found incidentally on screening chest computed tomography (CT) in asymptomatic subjects.
We included 56,358 consecutive participants (mean age 52.4 ± 10.5 years; male-female ratio 35,306:21,052) who underwent a baseline low-dose chest CT scan as part of a health checkup from 2006 through 2013. After the presence of anterior mediastinal nodular lesion had been confirmed, their CT findings, confirmatory diagnosis, and interval CT scan were reviewed. The standardized prevalence ratio for thymic epithelial tumor was calculated on the basis of the Republic of Korea cancer statistics for 2014.
Of the 56,358 participants, 413 (0.73%) had lesions (95% confidence interval: 0.66-0.80%); the prevalence increased with age (p <0.001) and a history of malignancy (p = 0.005). Of the lesions, 85.2% were smaller than 2 cm, 61.3% were round, and 80.2% had CT attenuation higher than 20 Hounsfield units. Among 51 proven cases, 39 lesions (76.9%) were benign and 12 (23.1%) were malignant. The standardized prevalence ratio for thymic epithelial tumor was 2.04 (95% confidence interval: 1.01-3.42). Of 11 resected thymic epithelial tumors, five were carcinomas, 10 were stage I or II, and all were completely resected without recurrence. Of the 237 unconfirmed cases with a follow-up CT scan, 82.2% were stable, 8.9% had increased, and the other 8.9% had decreased.
The prevalence of incidental nodular lesion was 0.73%. Most lesions had CT features that were indistinguishable from thymic epithelial tumors, but a considerable portion of the lesions were suspected to be benign. Incidental thymic epithelial tumors were more prevalent than clinically detected tumors, were early-stage cancer, and showed favorable outcomes.
本研究旨在调查无症状受检者在筛查性胸部计算机断层扫描（CT）中偶然发现的前纵隔结节性病变的发生率和特征。
我们纳入了 56358 例连续参与者（平均年龄 52.4±10.5 岁；男女性别比为 35306∶21052），他们在 2006 年至 2013 年间接受了作为健康检查的基线低剂量胸部 CT 扫描。在前纵隔结节性病变存在得到确认后，我们回顾了他们的 CT 结果、明确诊断和间隔 CT 扫描。根据 2014 年韩国癌症统计数据，计算了胸腺瘤的标准化患病率比。
在 56358 例参与者中，有 413 例（0.73%）存在病变（95%置信区间：0.66-0.80%）；患病率随年龄增长而增加（p<0.001），并与恶性肿瘤病史相关（p=0.005）。在病变中，85.2%小于 2cm，61.3%为圆形，80.2%的 CT 衰减值高于 20 个亨氏单位。在 51 例确诊病例中，39 个病变（76.9%）为良性，12 个（23.1%）为恶性。胸腺瘤的标准化患病率比为 2.04（95%置信区间：1.01-3.42）。在 11 例切除的胸腺瘤中，5 例为癌，10 例为Ⅰ期或Ⅱ期，且均完全切除，无复发。在 237 例未经证实且有随访 CT 扫描的病例中，82.2%稳定，8.9%增大，其余 8.9%减小。
偶然发现的结节性病变的发生率为 0.73%。大多数病变的 CT 特征与胸腺瘤无法区分，但相当一部分病变疑似为良性。偶然发现的胸腺瘤比临床检出的肿瘤更常见，为早期癌症，且预后良好。
