滤泡型甲状腺乳头状癌的超声表现及误诊分析

Follicular variant of papillary thyroid carcinoma:analysis of sonographic features and misdiagnosis

目的探讨滤泡型甲状腺乳头状癌(FV-PTC)的声像图特征,降低其术前超声误诊率。方法收集2010年6月至2012年12月福建医科大学附属协和医院经组织病理学证实的31例FV-PTC患者的35个结节,及66例经典型甲状腺乳头状癌(C-PTC)患者的75个结节,结合病理结果回顾性比较分析两组结节的超声声像图特征。结果 35个FV-PTC结节,29个超声表现为类圆形,7个纵横比>1,25个边缘不规则,18个为低回声,16个为等回声,15个不伴钙化,11个伴微钙化,9个伴粗大钙化,20个为无或少血流型,10个为边缘为主型血流,5个中央为主型血流。其中,纵横比>1、边缘不规则、极低回声、伴微钙化、中央为主型血流在FV-PTC结节的比率较C-PTC结节低,等回声、不伴钙化、边缘为主型血流在FV-PTC结节的比率较C-PTC结节高,且差异均有统计学意义[χ2=4.276,P=0.039;χ2=8.125,P=0.004;P=0.009(Fisher确切概率法);χ2=8.548,P=0.003;χ2=4.898,P=0.027;χ2=7.796,P=0.005;χ2=5.462,P=0.019;P=0.001(Fisher确切概率法)]。术前超声检查中,20个FV-PTC结节提示恶性,15个误诊为良性,误诊率43%(15/35)。FV-PTC患者颈部淋巴结转移率29%(9/31),低于C-PTC患者的62%(41/66),且差异有统计学意义(χ2=9.246,P=0.002);两组转移淋巴结的声像表现类似,少数缺乏恶性征象的FV-PTC癌结节术前超声根据淋巴结表现提示恶性。结论部分FV-PTC癌结节缺乏恶性征象,尤其在甲状腺多源发病的背景下易误诊为良性,多切面仔细观察每个甲状腺结节的纵横比、边缘、内部回声、钙化情况及血流模式等,并结合颈部淋巴结转移情况,对避免误诊有一定的意义。

Objective To investigate the sonographic features of follicular variant of papillary thyroid carcinoma （FV-PTC） and to decrease misdiagnosis rate. Methods Thirty-one patients with 35 FV-PTCs and 66 patients with 75 conventional PTCs （C-PTCs） were enrolled in this study. The sonographic features were reviewed retrospectively between the two groups with universally accepted standards. Results The sonographic features of 35 FV-PTCs included irregular shapes （6/35）, anteroposterior to transverse diameter ratio A/T 〉 1 （7/35）, spiculated margins （25/35）, marked hypoechogenicity （0/35）, hypoechogenicity （18/35）, isoechogenicity （16/35）, no calcification （15/35）, microcalcifications （11/35）, macrocalcification （9/35）, color Doppler lfow patternⅠ（20/35）, color Doppler lfow patternⅡ（10/35）, color Doppler lfow patternⅢ（5/35）. Irregular shapes, A/T〉1, spiculated margins, marked hypoechogenicity, microcalciifcations, and color type Ⅱ were rarer in FV-PTCs than in C-PTCs, while isoechogenicity, no calciifcation, macrocalciifcation, and color type Ⅲwere more frequent in FV-PTCs than in C-PTCs. The differences of the above features were statistically significant [χ^2=4.276, P=0.039; χ^2=8.125, P=0.004; P=0.009 （Fisher′ s exact test）; χ^2=8.548,P=0.003;χ^2=4.898, P=0.027,χ^2=7.796, P=0.005;χ^2=5.462, P=0.019;P=0.001 （Fisher′s exact test）] . During the preoperative ultrasonography, 20 of 35 FV-PTCs were diagnosed as malignancy, and others were misdiagnosed as benign nodules （misdiagnosis rate was 43%）. The lymphatic metastasis rate of FV-PTCs was 29%（9/31）, significantly lower than C-PTCs [62%（41/66）,χ^2=9.246, P=0.002]. In terms of the sonographic features of metastatic lymph nodes, there was no marked difference between FV-PTCs and C-PTCs. Conclusions Some FV-PTCs are lack of malignant features, and tend to be misdiagnosed frequently when coexisting with benign thyroid nodules. Observing the echogenicity, color lfow characteristics and other features of each thyroid nodule and cervical lymph node with multiple views may decrease the misdiagnosis rate.