Objective: To investigate the ultrasonographic features of medullary thyroid carcinomas (MTCs) of different sizes and supply valid information for separating MTCs from papillary thyroid carcinomas (PTCs). Methods: There were 87 patients with MTC and 220 patients with PTC detected by ultrasonography and confirmed by pathology at Tianjin Medical University Cancer Institute and Hospital from June 2018 to March 2022. Nodules were divided into the large nodule group (the maximum diameter of the tumor was＞1 cm) and the small nodule group (the maximum diameter of the tumor was ≤1 cm). There were 97 cases in the small nodule group, including 28 cases of MTC and 69 cases of PTC. There were 210 cases in the large nodule group, including 59 cases of MTC and 151 cases of PTC. After stratification by thyroid nodules, ultrasonographic features of thyroid nodules and metastatic lymph nodes, preoperative serum calcitonin (CT) and carcinoembryonic antigen (CEA) levels were compared between MTC and PTC patients. Results: In the small nodule group, the proportion of MTCs exhibiting hypoecho, smooth margins, and having blood flow signals was higher than that of PTCs, with statistically significant differences (all P＜0.05). In the large nodule group, the proportion of MTCs showing cystic solidity, hypoecho, smooth margins, blood flow, and the type Ⅳvascular distribution was higher than PTCs, and the difference of calcification type between them was also statistically significant (all P＜0.05). In contrast, the differences in the number of lesions and aspect ratio between MTCs and PTCs were not statistically significant regardless of nodule size (all P＞0.05). In the small nodule group,6 metastatic lymph nodes of medullary thyroid carcinoma (LNM-MTC) and 11 metastatic lymph nodes of papillary thyroid carcinoma (LNM-PTC) were correctly diagnosed by ultrasound, respectively. The diagnostic compliance rate of ultrasound was 78.6% (22/28) and 78.3% (54/69), respectively, with no statistically significant difference (P=0.973). In the large nodule group, 28 LNM-MTC and 11 LNM-PTC were correctly diagnosed by ultrasound, respectively. The diagnostic compliance of ultrasound was 88.1% (52/59) and 73.5% (111/151), respectively, which was statistically significant (P=0.022). Among them, 82.1% of LNM-MTC and 56.6% of LNM-PTC showed abnormal blood flow signals, with a statistically significant difference (P=0.016). There were significant differences in preoperative serum CT and CEA levels of different sizes of MTCs (all P＜0.05). Conclusions: Different sizes of MTCs require diverse demonstrative criteria. Abnormal blood flow signal is of great significance in the diagnosis of LNM-MTC. Within the absence of ultrasonic characteristics, preoperative serum CT test can provide confidence for the diagnosis of MTC.
目的： 探讨不同大小甲状腺髓样癌（MTC）的超声特征，为不同大小MTC和甲状腺乳头状癌（PTC）的鉴别诊断提供有效信息。 方法： 2018年6月至2022年3月在天津医科大学肿瘤医院超声检查发现并经病理证实的MTC患者87例，PTC患者220例。以甲状腺结节最大径1 cm为界值，将患者分为小结节组（最大径≤1 cm）和大结节组（最大径＞1 cm）。小结节组97例，其中MTC 28例，PTC 69例。大结节组210例，其中MTC 59例，PTC 151例。按甲状腺结节分层后，比较MTC与PTC患者甲状腺结节和转移性淋巴结的超声声像图特征、术前血清降钙素（CT）和癌胚抗原（CEA）水平。 结果： 在小结节组中，MTC表现为低回声、边缘光滑、有血流信号的比例高于PTC，差异有统计学意义（均P＜0.05）。在大结节组中，MTC表现为囊实性、低回声、边缘光滑、有血流、血管分布为Ⅳ型的比例高于PTC，并且MTC与PTC的钙化类型差异也有统计学意义（均P＜0.05）。而无论结节大小，MTC与PTC的病灶数量、纵横比差异均无统计学意义（均P＞0.05）。在小结节组中，分别有6例甲状腺髓样癌转移性淋巴结（LNM-MTC）和11例甲状腺乳头状癌转移性淋巴结（LNM-PTC）被超声正确诊断，超声对二者的诊断符合率分别为78.6%（22/28）和78.3%（54/69），差异无统计学意义（P=0.973）。大结节组中，分别有28例LNM-MTC和83例LNM-PTC被超声正确诊断，超声对二者的诊断符合率分别为88.1%（52/59）和73.5%（111/151），差异有统计学意义（P=0.022），其中82.1%的LNM-MTC和56.6%的LNM-PTC表现为血流信号异常，二者比较差异有统计学意义（P=0.016）。小结节组和大结节组MTC患者术前血清CT、CEA水平差异均有统计学意义（均P＜0.05）。 结论： 不同大小的MTC超声特征不同，淋巴结内异常血流信号对LNM-MTC的诊断具有重要意义。在缺乏超声特征的情况下，结合术前血清CT检测有助于MTC的诊断。.