Department of Ultrasound Diagnosis and Treatment, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin, 300060, China.
Key Laboratory of Cancer Prevention and Therapy, Tianjin, 300060, China.
Endocrine. 2021 Jun;72(3):727-734. doi: 10.1007/s12020-020-02510-2. Epub 2020 Oct 4.
Ultrasound (US) is the most important imaging in the preoperative diagnosis of medullary thyroid carcinoma (MTC). MTC are easy to be misdiagnosed due to lacking typical malignant US features. This study investigated US features, clinical characteristics, prognosis, and detection methods, aimed to explore the association between US features and biological behavior, and improve early diagnosis of MTC.
A total of 189 MTC patients were enrolled in the study. Based on US features, 29 MTC were categorized as "indeterminate" (i-MTC) and 160 MTC were categorized as "malignant" (m-MTC) according to Thyroid Imaging, Reporting and Data System published by America College of Radiology (ACR TI-RADS). We compared US features, clinical characteristics and prognosis between both groups. We analyzed cytological categories of fine needle aspiration (FNA) within each i-MTC and m-MTC group according to the 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We assessed the positive rate of FNA, frozen pathological examination, and preoperative serum calcitonin (Ctn) level in i-MTC and m-MTC groups.
Preoperative US features were significantly different in shape, margin, composition, echogenicity, and calcifications between i-MTC and m-MTC (p < 0.05). I-MTC showed a hypoechoic solid or solid-cystic nodule lacking malignant US features. While m-MTC was presented as a solid nodule with obviously malignant US features. There were significant differences in lymph node dissection, extent of tumor, lymph node metastasis, and TNM stage and prognosis between i-MTC and m-MTC (p < 0.05). Compared to m-MTC, i-MTC underwent central neck dissection more frequently rather than lateral neck dissection at the time of the initial operation; i-MTC had less extrathyroidal invasion and lymph node metastasis, earlier stage, higher rate of biochemical cure, and lower rate of structural persistence/recurrence (p < 0.05). The 2017 TBSRTC of i-MTC and m-MTC was significantly different (p < 0.05). Preoperative serum Ctn level had a higher diagnostic sensitivity for both i-MTC and m-MTC when comparing to FNA and frozen pathological examination (p < 0.05).
US features were associated with biological characteristics and prognosis of MTC. I-MTC lack malignant US features, preformed less aggressiveness, and better prognosis. TBSRTC according to FNA combined with serum Ctn were helpful for the detection of i-MTC.
超声（US）是甲状腺髓样癌（MTC）术前诊断中最重要的影像学检查。由于缺乏典型的恶性 US 特征，MTC 容易误诊。本研究探讨了 US 特征、临床特征、预后和检测方法，旨在探讨 US 特征与生物学行为的关系，提高 MTC 的早期诊断率。
共纳入 189 例 MTC 患者。根据美国放射学院（ACR）发布的甲状腺成像、报告和数据系统（Thyroid Imaging, Reporting and Data System，ACR TI-RADS），基于 US 特征，将 29 例 MTC 分为“不确定”（indeterminate，i-MTC），160 例 MTC 分为“恶性”（malignant，m-MTC）。我们比较了两组之间的 US 特征、临床特征和预后。我们根据 2017 年甲状腺细胞病理学报告 Bethesda 系统（Bethesda System for Reporting Thyroid Cytopathology，TBSRTC）对每个 i-MTC 和 m-MTC 组内的细针抽吸（fine needle aspiration，FNA）细胞学分类进行了比较。我们评估了 i-MTC 和 m-MTC 组中 FNA、冷冻病理检查和术前降钙素（calcitonin，Ctn）水平的阳性率。
术前 US 特征在形状、边界、成分、回声和钙化方面在 i-MTC 和 m-MTC 之间存在显著差异（p<0.05）。i-MTC 表现为缺乏恶性 US 特征的低回声实性或实性囊性结节。而 m-MTC 表现为具有明显恶性 US 特征的实性结节。i-MTC 和 m-MTC 之间在淋巴结清扫、肿瘤范围、淋巴结转移、TNM 分期和预后方面存在显著差异（p<0.05）。与 m-MTC 相比，i-MTC 在初始手术时更常接受中央颈部清扫，而不是侧颈部清扫；i-MTC 甲状腺外侵犯和淋巴结转移较少，分期较早，生化治愈率较高，结构残留/复发率较低（p<0.05）。2017 年 TBSRTC 在 i-MTC 和 m-MTC 之间存在显著差异（p<0.05）。与 FNA 和冷冻病理检查相比，术前血清 Ctn 水平对 i-MTC 和 m-MTC 的诊断敏感性更高（p<0.05）。
US 特征与 MTC 的生物学特征和预后相关。i-MTC 缺乏恶性 US 特征，侵袭性较小，预后较好。根据 FNA 联合血清 Ctn 的 TBSRTC 有助于 i-MTC 的检测。
