Endocrine Abstracts

Introduction: Fine needle aspiration biopsy (FNAB) plays a crucial role in the diagnosis of thyroid nodules. The choice of further therapeutic strategy depends largely on its result. Knowledge of the risk of malignancy in each diagnosis class in the population is necessary. The aim of the research was to analyse the risk of malignancy in thyroid nodules in each diagnosis class according to Bethesda system.

Materials and methods: Retrospective research included 1001 patients with thyroid nodules diagnosed and treated surgically between 2002 and 2015 in one department. Women accounted for 86% of the research group. The median age was 52 years. The results of the guided FNAB performed before the introduction of the Bethesda scale (621) were re-evaluated and qualified to the appropriate group according to the new criteria.

Result: The preoperative FNAB results presented as follows: non-diagnostic material (class I) – 6 (0.6%); benign (class II) – 522 (52.1%); follicular lesion of undetermined significance (class III, FLUS) – 62 (6.2%); suspicious for a follicular neoplasm (class IV, SFN) – 138 (13.8%); suspicious for malignancy (class V) – 74 (7.4%), malignant (class VI) –199 (19.9%). The postoperative histology follow-up in the research group were spread as follows: benign – 708 (70.7%); malignant – 292 (29.3%). Malignancy risk for each class according to Bethesda system amounted to respectively: I – 33%, II – 4.21%, III – 11.2%, IV – 13.04%, V – 59.46%, VI – 100%.

Conclusions: The present study shows that the risk of malignancy in class III and IV is low. The diagnosis of FLUS or SFN in the absence of clinical indications is not a basis for surgical treatment.