甲状腺发育异常超声表现及漏误诊分析

Comprehensive ultrasonic appearances contributing to the diagnosis of thyroid dysplasia and factors of misdiagnosis

目的总结甲状腺发育异常超声表现,并分析其漏误诊原因。方法回顾性分析2004年1月至2014年12月第二军医大学长征医院收治的205例甲状腺发育异常患者的超声声像图。其中170例患者以手术病理确诊,16例患者经穿刺活检病理确诊,19例患者以CT、MRI、发射型计算机断层成像影像学检查中2种以上检查结果一致支持甲状腺发育异常确诊。结果 205例患者中甲状舌管囊肿185例,甲状舌管瘘2例,甲状腺缺如4例,迷走甲状腺5例,副甲状腺9例。205例甲状腺发育异常患者超声正确诊断188例,诊断准确率为91.7%(188/205)。其中甲状舌管囊肿、甲状舌管瘘、甲状腺缺如、迷走甲状腺、副甲状腺的超声诊断准确率分别为92.4%(171/185)、50.0%(1/2)、100%(4/4)、80.0%(4/5)、88.9%(8/9)。超声漏诊5例:其中甲状舌管囊肿4例,迷走甲状腺1例。超声误诊12例:其中甲状舌管囊肿10例,4例超声误诊为颈部皮样囊肿,4例超声误诊为颈部脓肿,2例超声误诊为甲状腺峡部胶质潴留;甲状舌管瘘1例超声误诊为颈部脓肿;副甲状腺1例超声误诊为肿大淋巴结。超声正确诊断的171例甲状舌管囊肿患者中,161例超声表现为甲状腺与舌骨之间的区域内呈圆形、类圆形甚至条索状的无回声区,10例超声表现为颈前正中长椭圆形或不规则形低回声区;超声正确诊断的1例甲状舌管瘘患者超声表现为甲状舌管囊肿浅层向皮肤延伸的条索状低回声;4例甲状腺缺如患者超声表现为缺如侧的甲状腺床位置无甲状腺回声显示;超声正确诊断的4例迷走甲状腺患者超声表现为颈部正常位置无甲状腺显现,他处见类似甲状腺回声的结节;超声正确诊断的8例副甲状腺患者超声表现为颈部正常位置有甲状腺显现,他处见类似甲状腺回声的结节。结论甲状腺发育异常在超声表现上具有特征性。漏误诊影响因素包括超声检查者对颈部超声表现的熟知程度和经验、扫查技术的规范性、对可疑超声表现的质疑习惯以及主动拓展扫查范围乃至寻求其他影像学检查的意识。超声医师应熟悉其各种类型的超声声像图表现,掌握其超声检查的技术要领。

Objective To investigate the sonographic features of thyroid dysplasia for improving the diagnostic accuracy. Methods The data of 205 cases of thyroid dysplasia in Changzheng Hospital from January 2004 to December 2014 was investigated retrospectively. For confirming the diagnosis of thyroid dysplasia, surgical pathology, ultrasound-guided percutaneous core-needle biopsy and integration of computed tomography（CT）, magnetic resonance imaging（MRI） and emission computed tomography（ECT） findings were employed in 170, 16 and 19 cases respectively. Results As a final diagnosis of the 205 cases, 185 cases were diagnosed as thyroglossal duct cyst, 2 cases as thyroglossal fistula, 4 cases as thyroid absence, 5 cases as aberrant thyroid and 9 cases as accessory thyroid. Among them, accuracy rate of ultrasonic diagnosis was 92.4%（171/185） for thyroglossal duct cyst, 50.0%（1/2） for thyroglossal fistula, 100%（4/4） for thyroid absence, 80.0%（4/5） for aberrant thyroid and 88.9%（8/9） for accessory thyroid. Five cases were missed in ultrasonic diagnosis, which were 4 cases of thyroglossal duct cyst and 1 case of aberrant thyroid. Twelve cases were misdiagnosed by ultrasonography as follows： among the 10 thyroglossal duct cyst cases, four were mistaken as neck dermoid cyst, four as neck abscess, two as thyroid colloid retention. One case of thyroglossal fistula was mistaken as neck abscess. One case of accessory thyroid was mistaken as enlarged lymphatic node. In the 171 correctly diagnosed thyroglossal duct cyst, 161 cases has the ultrasonic features as follows： an anechoic lesion in round or oval shape located between thyroid and hyoid, while 10 cases have the appearance of oval or irregular-shaped hypoechoic lesion. The 1 case of thyroglossal fistula appeared in a stub-like hypoechoic lesion extending from a thyroglossal duct cyst-like structure to the subcutaneous layer. The 4 cases of thyroid absence have no presence of thyroid lobe in the thyroid bed. The 4 ultrasound correctly-diagnosed aberrant thyroid cause absence of thyroid glands in the thyroid bed, but presence of thyroid-like structure elsewhere. The 8 ultrasound correctly-diagnosed accessory thyroid not only have thyroid glands present in the thyroid bed, but also have presence of thyroid-like structure elsewhere. Conclusions The ultrasonic features of thyroid dysplasia can be characteristic to meet a correct diagnosis. The factors contributing misdiagnosis may be involved with the good awareness and experience of normal neck ultrasonography, the standard-operation of scanning, the consciousness of questioning suspicious sonographic scanning habits and expand the area of the initiative and even combine with other imaging modalities. The sonographer should be familiar with the various types of sonographic findings and key points of thyroid dysplasia.