Immunocytochemistry as an Adjunct to Fine-needle Aspiration of Thyroid in Distinction Between Benign and Malignant Thyroid Neoplasms

Introduction. Thyroid nodules are very common therefore distinction between benign and malignant tumors is essential for proper clinical management. Aim of the study. The study was performed to evaluate the diagnostic value of molecular markers in different thyroid tumors. Materials and methods. Forty-eight thyroid FNA cases confirmed by subsequent surgical resection specimens were selected. Immunocytochemistry for HBME-1, CD56 and E-cadherin (E-CAD) was performed. The study group consisted of 15 papillary thyroid cancers (PTC) and 1 follicular carcinoma (FC) as well as 12 follicular adenomas (FA) and 20 cases of colloid goiter (CG). Results. The expression of HBME-1 in PTC was significantly higher than in another thyroid lesions. E-CAD and CD56 expression was found in 8/12 (66.6%) and 6/12 (50%) cases of FA respectively. In contrast, PTC showed very low expression (1/15) of both E-CAD and CD56. Expression of the three analyzed markers was not more than 10% in case of CG. Conclusions. We concluded that immunocytochemical (ICC) staining is of value as an ancillary test to enhance the diagnostic accuracy of thyroid FNA biopsies. Larger studies dedicated to evaluate the role of these or other markers for distinction between FC and FA can be particularly useful. We recommend the small panel consisting of three ICC markers, HBME-1, E-CAD and CD56 as an adjunct to standard cytomorphology criteria to enhance the diagnostic accuracy of thyroid nodules with follicular-patterned cytologic features.