EXPRESSION OF CD56, CK19 AND HBME-1 IN FOLLICULAR VARIANT OF PAPILLARY THYROID CARCINOMA AND BENIGN MIMICKERS
Objective: To assess the diagnostic utility of a set of 3 markers i.e. CD56, CK-19 and HBME-1 to differentiate follicular variant of papillary carcinoma (FVPC) from its benign mimickers.
Material and Methods: This is a prospective cross-sectional study conducted at Histopathology department of Armed force institute of pathology (AFIP) Rawalpindi, Pakistan from May 2020 to Aug 2020. A cross-sectional study in which samples of 40 thyroid lesions that included 20 FVPTC and 20 hyperplasia/adenomas were retrieved from the database of the Department of Histopathology of Armed Forces Institute of Pathology, Rawalpindi. Immunohistochemistry was done to assess the expression of CD56, CK19 and HBME-1 in FVPTC (n=20) and hyperplasia/adenoma (n=20). Results were analyzed using SPSS 21.
Results: Strongly positive (2+) staining with CK19 and HBME-1 was observed in 95% and 80% of the FVPTC patients respectively. Expression of CD56 was negative in 80% of FVPTC. A significant statistical difference was observed in the expression of HBME-1, CK19 and CD56 in FVPTC and benign lesions (P<0.05).
Conclusion: Negative staining for CD56 in a thyroid lesion while at the same time co-expression of diffuse and strong staining with CK19 and HBME-1 in a follicular pattern lesion posing a diagnostic challenge is highly suggestive of FVPTC provided it is interpreted in the right context.
Key Words: Immunohistochemistry, CD56, HBME-1, CK19, Follicular variant of papillary carcinoma.