ECE2014 Poster Presentations Endocrine tumours and neoplasia (99 abstracts)
1Unit of Endocrinology and Metabolism, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; 2Azienda USL of Modena, Modena, Italy; 3Center of Genomic Research of the University of Modena and Reggio Emilia, Modena, Italy; 4Department of Laboratories and Pathologic Anatomy, University of Modena and Reggio Emilia, Modena, Italy.
Objective: Thyroid fine-needle aspiration (FNA) cytology is indeterminate in 1525% of cases. Recently, cytological analysis was combined to molecular analysis to improve diagnostic accuracy. In the present study, washing liquid of FNA (wFNA) samples were tested for the BRAF V600E mutation, using high resolution melting (HRM) technology. The aim of this study was to demonstrate whether BRAF mutation analysis is accurate in wFNA and, when combined with cytological analysis and ultrasonography (US), can serve as an additional diagnostic tool.
Methods: Study design: cohort study involving 481 patients, corresponding to 648 FNA samples. All samples were subjected to both cytological and molecular analysis on the same aspiration: the former was conducted on cells smeared on a glass slide, the latter was carried out on fluids obtained washing the FNA needle with 2 ml of saline. BRAF V600E mutation analysis was performed by HRM after careful methodological validation for application to wFNA (sensitivity: 5%).
Results: The cytological results of the 648 FNA were: 136 (21%) non diagnostic (Thy 1); 415 (64%) negative for malignant cells (Thy 2); 80 (12.4%) inconclusive/indeterminate (Thy 3); 9 (1.4%) suspicious for malignancy (Thy 4); 8 (1.2%) diagnostic for malignancy (Thy 5). The BRAF V600E mutation was found in 2 (2.5%) Thy 3, 6 (66.6%) Thy 4 and 6 (75%) Thy 5. Surprisingly, 5 (1.2%) Thy 2 samples resulted BRAF mutated. BRAF V600E mutations were confirmed by pyrosequencing in scraped Thy 2 cytological samples. Patients underwent thyroidectomy and the diagnosis of papillary carcinoma was confirmed at histology.
Conclusions: This study demonstrates that BRAF assessment can be accurately performed on wFNA and improves the diagnostic performance, regardless of cytological results. In perspective, stand-by wFNA samples could be analyzed a posteriori in case of indeterminate cytology and/or suspicious US findings.