A Monocentric Retrospective Study about the Correlation between Histology and Cytology of Thyroid Indeterminate Nodules Classified as TIR 3A and TIR 3B, according to 2014 Italian Consensus for Classification and Reporting of Thyroid Cytology.

150 patients have been analyzed for the research; 62 (41.3%) had a malignant histological report. Rates of malignancy between TIR 3A (20.8%) and TIR 3B (60.3%) were significantly different (p < 0.0001). The subclassification had high sensitivity (75.8%; CI 63.3-85.8%) and NPV (79.3%; CI 68-87.8%) and low specificity (64.8%; CI 53.9-74.7%) and PPV (60.3; CI 48.5-71.2%). The measurement of the accuracy (AUC = 0.7) classified the test as "moderately accurate." Conclusions. Obtained data show a great rate of false negative (20.8%) and limited AUC (0.7). According to our logistic regression, we argue that the 2014 subclassification into TIR 3A and TIR 3B should be considered for the choice of patient treatment, but at the same time, we believe that the association with other screening tests is necessary to increase the accuracy in the future.