Abdou Asmaa Gaber, Shabaan Mohammed, Abdallha Rania, Nabil Nehal
Department of Pathology, Faculty of Medicine, Menoufia University, Shebein Elkom, Egypt.
Clin Pathol. 2019 Jul 22;12:2632010X19863047. doi: 10.1177/2632010X19863047. eCollection 2019 Jan-Dec.
Papillary thyroid carcinoma (PTC) represents the most common primary malignant thyroid tumor and its diagnosis is dependent on the presence of classic nuclear features that are sometimes seen in some non-neoplastic and benign lesions. Several immunohistochemical markers are used individually or in combination to help in differentiation of PTC from mimickers. The aim of the current study was to assess the diagnostic value of TROP-2 and cytokeratin 19 (CK19) expression in differentiating PTC from other mimickers both singly and in combination. The current study was carried out on 77 surgical specimens (56 PTC and 21 non-neoplastic cases) and 12 cytological specimens (4 THY2, 6 THY4, and 2 THY5). TROP-2 was negative in 81% of non-neoplastic surgical specimens and in 100% of THY2 cytological specimens while it was positive in 71.4% of PTC surgical specimens and 100% of THY4/THY5 cytological specimens. Sensitivity and specificity of TROP-2 positive expression for diagnosis of PTC in surgical specimens reached 71% and 81%, respectively, while it reached 100% for both in cytological specimens. Cytokeratin 19 showed positive expression in 85.7% of non-neoplastic surgical specimens and in 92.9% of PTC surgical specimens. Cytokeratin 19 showed negative expression in 75% of Thy2 cases while it was positive in all studied Thy4 and Thy5 cases. Sensitivity and specificity of CK19 total estimated score for diagnosis of PTC in surgical specimens were 78.6% and 66.7%, respectively, while it reached 100% and 75% in cytological specimens. Positive TROP-2 and CK19 expression in PTC were associated with lymph node metastasis. TROP-2 is a specific rather than sensitive marker while CK19 is a sensitive rather than specific marker in differentiating PTC from other mimickers in surgical specimens. The diagnostic validity of both markers was superior in diagnosis of classic PTC compared with follicular variant PTC. TROP-2 is superior to CK19 in diagnosis of PTC in cytological specimens. Both TROP-2 and CK19 could be used preoperatively in adjunct to hematoxylin and eosin for more confident diagnosis of thyroid cytology and along with radiology as predictors of lymph node metastasis.
乳头状甲状腺癌（PTC）是最常见的原发性甲状腺恶性肿瘤，其诊断依赖于经典的核特征，而这些特征有时在一些非肿瘤性和良性病变中也可见。几种免疫组化标志物单独或联合使用，以帮助将PTC与相似病变区分开来。本研究的目的是评估TROP-2和细胞角蛋白19（CK19）表达在单独及联合使用时鉴别PTC与其他相似病变的诊断价值。本研究对77份手术标本（56例PTC和21例非肿瘤性病例）和12份细胞学标本（4例THY2、6例THY4和2例THY5）进行了研究。TROP-2在81%的非肿瘤性手术标本和100%的THY2细胞学标本中呈阴性，而在71.4%的PTC手术标本和100%的THY4/THY5细胞学标本中呈阳性。TROP-2阳性表达诊断手术标本中PTC的敏感性和特异性分别达到71%和81%，而在细胞学标本中两者均达到100%。细胞角蛋白19在85.7%的非肿瘤性手术标本和92.9%的PTC手术标本中呈阳性表达。细胞角蛋白19在75%的Thy2病例中呈阴性表达，而在所有研究的Thy4和Thy5病例中呈阳性表达。手术标本中CK19总估计评分诊断PTC的敏感性和特异性分别为78.6%和66.哪7%，而在细胞学标本中分别达到100%和75%。PTC中TROP-2和CK19阳性表达与淋巴结转移相关。在手术标本中，将PTC与其他相似病变区分开来时，TROP-2是一个特异性而非敏感性标志物，而CK19是一个敏感性而非特异性标志物。与滤泡状变异型PTC相比，这两种标志物在经典PTC的诊断中诊断效能更高。在细胞学标本中诊断PTC时，TROP-2优于CK19。TROP-2和CK19均可在术前辅助苏木精和伊红染色，以更准确地诊断甲状腺细胞学，并与放射学一起作为淋巴结转移的预测指标。
