Utility of immunohistochemical markers in differentiating benign from malignant follicular-derived thyroid nodules

BACKGROUND Thyroid nodules are common among adults though only a small percentage is malignant, which can histologically mimic benign nodules. Accurate diagnosis of these thyroid nodules is critical for the proper clinical management. METHODS We investigated immunoexpression in 98 surgically removed benign thyroid nodules including 52 hyperplastic nodules (HN) and 46 follicular/Hurthle cell adenomas (FA), and 54 malignant tumors including 22 follicular carcinoma (FC), 20 classic papillary carcinoma (PTC), and 12 follicular variant papillary carcinoma (FVPC). RESULTS The staining results showed that malignant tumors express galectin-3, HBME-1, CK19 and Ret oncoprotein significantly more than benign nodules. The sensitivity of these markers for the distinction between benign and malignant lesions ranged from 83.3% to 87%. The sensitivity of two-marker panels was not significantly different. Immunoexpression was usually diffuse and strong in malignant tumors, and focal and weak in the benign lesions. CONCLUSION Our findings indicate that these immunomarkers are significantly more expressed in malignant tumors compared to benign lesions and may be of additional diagnostic value when combined with routine histology.