Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
Korean J Radiol. 2020 Oct;21(10):1187-1195. doi: 10.3348/kjr.2019.0983. Epub 2020 Jul 17.
This study aimed to determine the sonographic features suggestive of extrathyroidal extension (ETE) of thyroid cancers.
We retrospectively reviewed the sonographic images of 1656 consecutive patients who had undergone thyroidectomy in 2017. The diagnostic performance of sonographic features suggestive of ETE was evaluated using operation and histopathologic reports. Sonographic features for gross ETE to the strap muscle and minor ETE were assessed for thyroid cancer abutting the anterolateral thyroid capsule. Sonographic features for tracheal invasion were assessed according to whether the angle between the tumor and the trachea was an acute, right, or obtuse angle. Sonographic features for recurrent laryngeal nerve (RLN) invasion were assessed based on the association between the tumor and tracheoesophageal groove (TEG) as preserved normal tissue, abutting or protruding into the TEG.
ETE was observed in 783 patients (47.3%), including 123 patients with gross ETE (7.4% [strap muscle, n = 97; RLN, n = 24; and trachea, n = 14]) and 660 patients with minor ETE (39.9%). Regarding the diagnosis of gross and minor ETE to the strap muscle, sonographic features of replacement of the strap muscle and capsular disruption showed the highest positive predictive value (75.9% and 58.5%, respectively). Thyroid cancer forming an obtuse angle with the trachea had the highest sensitivity for the diagnosis of tracheal invasion (85.7%), and thyroid cancer protrusion into the TEG showed the highest sensitivity for the diagnosis of RLN (83.3%).
Sonography is considered beneficial in the diagnosis of ETE to the strap muscle, trachea, and RLN. Assessment of ETE is important for the accurate staging of thyroid cancer, which in turn determines the extent of surgery or whether active surveillance is appropriate or not.
本研究旨在确定提示甲状腺癌甲状腺外延伸（ETE）的超声特征。
我们回顾性分析了 2017 年接受甲状腺切除术的 1656 例连续患者的超声图像。使用手术和组织病理学报告评估提示 ETE 的超声特征的诊断性能。评估甲状腺癌前侧甲状腺包膜贴附的粗颈肌和小 ETE 的大体 ETE 的超声特征。根据肿瘤与气管之间的角度是锐角、直角还是钝角来评估气管侵犯的超声特征。根据肿瘤与气管食管沟（TEG）之间的关系评估喉返神经（RLN）侵犯的超声特征，如果肿瘤与 TEG 是作为正常保留组织贴附还是突出到 TEG 中。
783 例患者（47.3%）存在 ETE，包括 123 例粗颈肌 ETE（7.4%[颈肌，n=97；RLN，n=24；气管，n=14]）和 660 例小颈肌 ETE（39.9%）。对于粗颈肌和小颈肌的大体和小颈肌 ETE 的诊断，颈肌替代和包膜破坏的超声特征具有最高的阳性预测值（分别为 75.9%和 58.5%）。与气管形成钝角的甲状腺癌对诊断气管侵犯具有最高的敏感性（85.7%），而向 TEG 突出的甲状腺癌对诊断 RLN 具有最高的敏感性（83.3%）。
超声在诊断颈肌、气管和 RLN 的 ETE 方面被认为是有益的。评估 ETE 对于准确分期甲状腺癌很重要，这反过来又决定了手术的范围或是否需要积极监测。
