Immunocytochemical analysis for differential diagnosis of thyroid lesions using liquid-based cytology.

Recently, liquid-based cytology (LBC) has been widely applied to various samples in diagnostic cytology and its usefulness has been reported. In this study, we investigated thyroid cytology that applied LBC and immunocytochemistry to achieve more objective diagnosis and greater diagnostic accuracy. This study included 125 cases (57 papillary carcinomas (PCs), 22 follicular tumors, 43 adenomatous goiters and 3 with Basedow's disease). After preparing the LBC slide, immunocytochemical staining was performed on each slide with six antibodies (HBME-1, cytokeratin 19 (CK19), high molecular weight cytokeratin (34JE12), galectin-3, CD15 and CA 19-9). All antibodies presented immunopositivity frequently in PCs, but only a few or some of them were positive in other cases. These antibodies were considered positive markers for PCs, and the most reliable marker was 34betaE12; its sensitivity, specificity and diagnostic accuracy were 82.5%, 100% and 92.0%, respectively. Relations of immunocytochemical profiles against these markers were assessed using panel 34betaE12, GAL-3 and CK19. More than or equal to two of these markers showed co-positive in 53 of 57 PCs, and negative for all markers was observed in only one case. In the other (non PC) cases, the former was 0 of 58 and the latter was 40 cases. In this panel, the sensitivity, specificity and diagnostic accuracy were 93.0%, 100% and 96.8%, respectively. All of these values were higher than or equal to single values of 34betaE12. We concluded that the panel in this study is useful for more objective and accurate diagnosis of thyroid cytology.