DIAGNOSTIC AND PROGNOSTIC VALUE OF IMMUNOCYTOCHEMISTRY AND BRAF MUTATION ANALYSIS ON LIQUID BASED BIOPSIES OF THYROID NEOPLASMS SUSPICIOUS FOR CARCINOMA

OBJECTIVE: In the field of Fine Needle Aspiration Cytology (FNAC), the category of suspicious for malignancy (SM) thyroid lesions which bears 55-85% risk of malignant histology, is a challenging topic in which morphology alone is not always able to make a correct diagnosis. Recently, immunocytochemistry (ICC) has been referred as helpful in differentiating low and high malignant risk lesions and BRAF activating mutations have been identified in a significant amount of papillary thyroid carcinomas (PTC). The introduction of the liquid-based cytology (LBC) may simplify the application of these techniques to thyroid cytology.DESIGN Our aim is to evaluate the diagnostic and prognostic role of both ICC and BRAF mutation for the SM category on LBC.METHODS From October 2010 through June 2011, 113 LBC cytological cases (including 37 SM and 76 PTC) underwent surgery. All cases were studied for BRAF mutation and ICC.RESULTS In detail, ICC resulted positive in 26 (86.6%) histologically malignant SM with 15 of which (40.5%) expressed a BRAF mutation. Overall 63 cases showed a BRAF mutation histological resulting as PTC.Concerning the prognostic role of BRAF mutation for the two categories, we reported a significant correlation with multifocality, nodal involvement and extracapsular invasion (p<0.0001).CONCLUSIONS Special techniques such as ICC and molecular might be successfully carried out on LBC- processed material. For both categories, ICC is more sensitive whereas BRAF analysis is an interesting support due to its high specificity adding a prognostic value in both SM and PTCs.