The aim of the study was to evaluate the expression of galectin-3 (gal3), cytokeratin 19 (CK19), neural cell adhesion molecule (NCAM), and E-cadherin (Ecad) in thyroid gland tumors with follicular growth pattern with particular focus on their use in differential diagnosis. A series of 139 cases – 87 follicular adenomas (FAs), 26 follicular carcinomas (FCs), and 26 cases of the follicular variant of papillary carcinoma (FVPC) was studied. Expression of gal3 was found in 29/87 (33%) of FAs, in 13/26 (50%) of FCs, and in 24/26 (92%) of FVPCs. Expression of CK19 was found in 11/87 (13%) of FAs, in 4/26 (15%) of FCs, and in 17/26 (65%) of FVPCs. Expression of NCAM was found in 60/87 (69%) of FAs, in 20/26 (77%) of FCs, and in 7/26 (27%) FVPCs. Expression of Ecad was found in 81/87 (93%) of FAs, in 22/26 (85%) of FCs, and in 17/26 (65%) of FVPCs. The sensitivity and specificity of gal3 for malignancy were 0.70 and 0.85, of CK19 0.48 and 0.98, of NCAM 0.28 and 0.47, and of Ecad 0.48 and 0.20, respectively. A significant difference (p < 0.05) in expression of all studied markers between FVPC versus FA and FC was found, in contrast to FA and FC. Therefore, the use of gal3 and CK19 in differential diagnosis of FVPC versus FA and FC can be recommended.

        Key words: thyroid gland – tumors – galectin-3 – cytokeratin 19 – neural cell adhesion molecule – E-cadherin