Contribution of immunocytochemical stainings for galectin-3, CD44, and HBME1 to fine-needle aspiration cytology diagnosis of papillary thyroid carcinoma.

In cytology practice some papillary thyroid carcinoma (PTC) cases have indeterminate diagnoses and overlapping cytological features with benign lesions. This study was undertaken to find out if immunocytochemistry using Galectin-3, CD-44 and HBME-1 could be of help in such situations. Forty-six cases consisting of 22 malignancy (PTC) cases, 7 suspicious of (S/O) PTC, 1 follicular neoplasm, 5 follicular lesion of undetermined significance (FLUS), and 11 benign (colloid goiter) cases diagnosed by FNA were included in this study. Staining reactions were graded in a sliding scale of -, 1+, 2+, 3+, and 4+. In an assessment of 100 cells, each cell with weak, and moderate to strong positive reaction were assigned a score of 1 and 4, respectively. Staining reaction of ≥+2 and scores >100 were considered positive. Frequency of cases with ≥+2 reaction, and scores >100 for each of Galectin-3, CD-44, and HBME-1 were significantly higher in PTC or combined PTC and S/O PTC cases as compared with FLUS and benign cases taken together (P = 0.01744 to 0.00000). When the cases were compared according to histological malignant and benign diagnoses, the difference was also significant in respect of ≥+2 reaction, and scores >100 for Galectin-3 and CD44 (P = 0.04923 to 0.00947); however, there was no significant difference, when these parameters for HBME1 were compared. Galectin 3, CD 44, and to some extent HBME 1 are useful immunocytochemical parameters with potential to support FNAC diagnosis of PTC, especially in situations with difficult differential diagnoses.