Endocrine Abstracts

Introduction: Regarding thyroid nodules, in case of follicular lesion of undetermined significance (FLUS), performing repeat fine-needle aspiration (FNA) is a common follow-up strategy. It has been suggested that a waiting period of at least 3 months between FNAs would increase the diagnostic yield. Our study aims to clarify the optimal time for repeat FNA in case of an initial FLUS result.

Methods: We identified retrospectively all thyroid FNA FLUS results that occurred in our institution in 2016 and analysed only the patients who were submitted to repeat FNA. We recorded cytologic diagnosis, time between FNA and histologic results in case of surgery.

Results: A total of 79 patients were included, with ages between 34 and 86 years. Mean nodule diameter was 26.7±11.7 mm. After the second FNA, 8 (10.18%) patients also underwent a third one. A total of 6 (7.6%) had surgery performed at some time during follow-up – 2 cases with malignant histology results. The result of the second FNA was non-diagnostic in 27.8% of cases and remained FLUS in 26.6%. Mean time interval between the first and second FNA was 3.8±1.4 months. We did not find a statistically significant difference in diagnostic yields (P=0.267) or diagnostic non-FLUS results (P=0.523) between second FNA’s performed 3 months or earlier (36 patients) compared to those preformed later (43 patients). Timing (as well as sex, age and nodule diameter) remained not correlated with diagnostic yield or diagnostic non-FLUS results after regression analysis using time between FNAs as a continuous variable.

Conclusion: Although our study had limited numbers, its results suggest that in case of a first FLUS FNA result, and if the decision to repeat is considered by the clinician, the timing of the second FNA does not seem to affect its diagnostic yield or the likelihood of another FLUS result.