Endocrine Abstracts

In thyroid nodules with indeterminate cytology, presurgical evaluations for risk management comprise biochemical tests, ultrasonography (US), elastography-US (USE), contrast-enhanced US (CEUS) and mutation analysis. The cytology of 130 Thy 3 nodules was reviewed according to the BTA 2014 classification. Nodules were divided into Thy 3a and Thy 3f categories. Histology was available in 97 nodules. Malignancy was the final diagnosis in 19% of surgically treated nodules. No significant difference in the risk of malignancy was found between Thy 3a (26%) and Thy 3f (14%) nodules. Post-surgical histologic examination of the Thy 3a and Thy 3f nodules showed a higher incidence of Hurtle cell adenomas in Thy 3f (29%) than in Thy 3a (3%) nodules (P=0.01). BRAF V600E mutation was positive in some Thy 3a but not in any Thy 3f nodules (P=0.04). Cut-off values by ROC analysis from US (score), USE (ELX 2/1 strain index) and CEUS (time-to-peak index and peak index) were similar in Thy 3a and Thy 3f nodules. Data showed that malignancy can be suspected if the US score is >2, ELX 1/2 strain index >1, time–to-peak index >1 and peak index <1. In a group of 24 revised nodules (12 Thy 3a and 12 Thy 3f) the diagnostic power of cumulative pre-surgical analysis by means of US, USE and CEUS showed high positive and negative predictive values (83% and100%, respectively) for the presence of malignancy in Thy 3a and Thy 3f nodules. In our series of revised Thy 3 nodules, malignancy was low and displayed no significant differences between Thy 3a and Thy 3f categories. The use of cut-offs based on histology as a reference, in both Thy 3a and Thy 3f nodules, could reduce surgery. In mutation-negative Thy 3 nodules, observation should be the first choice when not all instrumental results are suspect.