甲状腺微小癌的超声征象及漏诊原因分析

Sonographic appearances of thyroid microcarcinoma and analysis of missed diagnosis

目的分析甲状腺微小癌的超声征象及漏诊原因。方法回顾性分析47例(54个)甲状腺微小癌的超声征象及漏诊原因。结果本组54个结节,超声检出52个(96.3%),2个(3.7%)被漏诊。25个术前超声检查提示恶性,16个提示可疑恶性,11个提示良性,超声诊断符合率78.8%(41/52)。同时合并甲状腺良性疾病29例,其中包括9例超声检查提示良性者。超声征象特征:边界不清晰41个(78.8%)、形态不规整37个(71.2%),低回声49个(94.2%),含钙化30个(57.7%)及无血流25个(48.1%),少许血流12个(23.1%),丰富血流15个(28.8%)。11个误诊良性的结节中8个(72.7%)边界清晰,9个(81.8%)形态规整,9个(81.8%)低回声,10个(90.9%)纵横比<1,9个(81.8%)无钙化及6个(54.5%)无血流。结论甲状腺微小癌的超声表现虽然具有一定的特征性,但因径线较小容易误诊,应强调综合分析。癌结节甲状腺被膜接触面与结节周长之比对于判断外侵有帮助。

OBJECTIVE To investigate the sonographic appearances of thyroid microcarcinoma and to analyze the reasons of the missed diagnosis. METHODS The ultrasonographic characteristics of 47 cases(54nodules) of thyroid microcarcinoma and missed diagnosis were reviewed ret rospectively. R ESU LTS There were 54 nodules in total, and 52(96.3%) of them were detected by ultrasonography. The other 2(3.7%) nodules were undetected. Twenty-five nodules were diagnosed as malignant, 16 were suspected malignant, and 11 were benign.The diagnostic rate of the ultrasonography was 78.8%(41/52)compared to the histopathological results. Benign diseases of the thyroid gland were found accompanied with thyroid microcarcinoma in 29 cases. Of them, 11 microcarcinoma nodules in 9 cases were missed. There were 41(78.8%)nodules with unclear boundary,37(71.2%)nodules with irregular shape,49(94.2%)nodules with hypoechoic scan,30(57.7%) nodules with calcification, 25(48.1%) nodules with avascular scan, 12(23.1%)nodules with little vascular scan, and 15(28.8%) nodules with abundant vascular scan. Of the 11 misdiagnosed nodules, 8(72.7%) had clear boundary, 9(81.8%) nodules had regular shape, 9(81.8%)nodules had hypoechoic scan, 9(81.8%) nodules had noncalcification,6(54.5%) nodules had avascular scan and the vertical and horizontal diameter ratio of the 10(90.9%)nodules were less than one. CONCLUSION Thyroid microcarcinoma has certain characteristics on sonography imaging, though the misdiagnosis is not uncommon due to the small diameter. Comprehensive analysis of these appearances is emphasized for the diagnosis. The perimeter ratio for the contact area between the nodule and the capsule of thyroid gland are helpful to determine the invasion.