甲状腺过氧化物酶免疫染色在甲状腺细针抽吸细胞学检查中的诊断作用

Diagnostic value of thyroid peroxidase immunostaining in the fine needle aspirated thyroid tumor cells

目的评价甲状腺过氧化物酶（TPO）在甲状腺细针抽吸细胞学检查中对良恶性甲状腺肿瘤的鉴别价值。方法采用免疫染色法观察TPO的单克隆抗体MoAb47在71例甲状腺肿瘤患者的甲状腺细针抽吸标本涂片中的表达，免疫染色结果的阳性判定根据两种不同方法进行：（1）De Mieeo法：80％以上甲状腺细胞染色为阳性，反之为阴性。（2）常规病理学法：5％或以上甲状腺细胞染色为阳性，低于5％甲状腺细胞染色为阴性。结果TPO在恶性甲状腺肿瘤细胞中的表达明显低于良性甲状腺肿瘤细胞。De Mieeo法和常规病理学法的敏感度和特异度分别为95．74％和91．67％、100．00％和58．33％；阳性及阴性预测值分别为95．74％和91．67％、82．46％和100．00％。结论TPO免疫染色用于甲状腺细针抽吸细胞学检查，可以提高甲状腺肿瘤的正确诊断率，而结果判定的方法不同可能影响TPO对甲状腺肿瘤的诊断价值。

Objective To evaluate immunostaining using the monoclonal antibody MoAM7 against thyroid peroxidase （TPO）in distinguishing between benign and malignant thyroid tumor ceils in fine needle aspiration cytology （FNAC） samples. Methods Fine needle aspirates （FNA） samples and frozen tissue sections were stained by immunocytochemistry using TPO MoAb47. Positive result of TPO immuno staining were judged by two methods ： （1） De Micco method： samples were considered benign if more than 80% more of the thyroid cells of thyroid tumor were stained by TPO. Consequently, samples were considered malignant if 20% or more of the thyroid cells failed to stain for TPO. （2）Classical pathologic method：cases that showed specific staining of 5% or more of the tumor cells, regardless of staining intensity, were scored as positive for TPO. A negative result for TPO was considered consistent with cancer. Results Pattern with negative TPO staining in FNAC samples was found in 22 out of 24 which were diagnosed malignant tumor by histological pathology, while positive TPO staining pattern was found in 45 of 47 FNAC samples of benign tumor, with sensitivity and specificity at 95.74% and 91.67% respectively, judging by De Micco method. And negative TPO staining was found in 14 out of 24 which were diagnosed malignant tumor by histological pathology, with sensitivity and specificity at 100. 00% and 58.33% respectively, judging by classical pathologic method. Conclusion TPO has been proved to be a good marker serving for FNAC distinguishing between benign and malignant thyroid nodules. TPO immunostaining can be used in fine needle aspirates as a reliable tool to improve FNAC diagnosis, but the application would be limited by the judgment method.