Galectin-3 and HBME-1 improve the accuracy of core biopsy in indeterminate thyroid nodules

Core needle biopsy (CNB) has been recently described as an accurate second-line test in thyroid inconclusive cytology (FNA). Here we retrospectively investigated the potential improvement given by Galectin-3, Cytokeratin-19, and HBME-1 on the accuracy of CNB in thyroid nodules with prior indeterminate FNA report. The study included 74 nodules. At CNB diagnosis, 15 were cancers, 40 were benign, and 19 had uncertain/non-diagnostic CNB report. The above immunohistochemical (IHC) panel was analyzed in all cases. After surgery, 19 malignant and 55 benign lesions were found. All 15 cancers and all 40 benign nodules diagnosed at CNB were confirmed at final histology. Regarding the uncertain CNB group, 4 (21 %) were malignant and 15 (79 %) benign. When we considered all the series, the most accurate IHC combination was Galectin-3 plus HBME-1, while HBME-1 was the most sensitive marker in those nodules with uncertain CNB report. The combination of CNB plus IHC could indentify 19/19 cancers and 53/55 benign lesions. Sensitivity and specificity of CNB increased from 79 to 100 % and from 73 to 96 %, respectively, by adding IHC. CNB can diagnose the majority of thyroid nodules with previous indeterminate FNA cytology, while the accuracy of CNB is increased by adding Galectin-3, Cytokeratin-19, and HBME-1 panel. We suggest to adopt CNB as a second-line approach to indeterminate thyroid FNA, and apply IHC in those lesions with uncertain/non-diagnostic CNB report. This approach should improve the pre-surgical diagnosis of patients. These results should be confirmed in larger prospective series.