Reproducibility of 'The Bethesda System for reporting Thyroid Cytopathology': A MultiCenter Study with Review of the Literature.

Background: To achieve the standardization of the thyroid FNA reporting, the National Cancer Institute (NCI) hosted the "NCI Thyroid Fine Needle Aspiration State of the Science Conference", which led to the formation of 'The Bethesda System for Reporting Thyroid Cytopathology' (TBSRTC).

Material And Methods: The present study was undertaken by 2 experts in thyroid FNA, who in a double blinded fashion, examined and re-classified 80 random FNA cases according to the 6 levels of TBSRTC for an inter-observer review, to study and assess the new terminology for ease of reproducibility and to note the rate of disagreement overall or in any particular category. The FNAs were reclassified in a double blinded fashion according to the 6 levels of TBSRTC which are: non diagnostic (ND); benign; atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS); follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN), Hurthle cell type/suspicious for a follicular neoplasm, Hurthle cell type (FNHCT/SFNHCT); suspicious (SUS), and malignant.