Endocrine Abstracts

Objectives: In the 5th edition of the WHO Classification of Endocrine and Neuroendocrine Tumors thyroid tumors are divided into several new categories that allow for a clearer understanding of the cell of origin, pathologic features, molecular classification, and biological behavior. According to this classification there are some borderline nodules -the group of low-risk follicular cell-derived neoplasms - such as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), follicular tumor of uncertain malignant potential (FT-UMP) and well-differentiated tumor of uncertain malignant potential (WDT-UMP). The diagnosis is possible only postoperative based on histopathologic results. In order to raise suspicion of borderline lesions preoperatively, the outcomes of sonographic and cytopathological patterns of thyroid nodules were analysed.

Methods: In the present study we retrospectively analysed thyroid nodules of the 35 patients operated on in 2022 diagnosed with NIFTP, FT-UMP and WDT-UMP in final pathology. Sonographic features of nodules including elastography and contrast-enhanced ultrasound (CEUS) were evaluated by two experienced specialist and the risk of malignancy were assessed according to EU-TIRADS classification.

Results: Final histopathologic results included 35 thyroid nodules (in 30 women and 5 men, age ranged: 20-81, diameter range: 6-55,5mm [mean: 28.7]) diagnosed as NIFTP (n=7, 20%), FT-UMP (n=21, 60%) and WDT-UMP (n=7, 20%). Cytopathological results were categorised as follows: Bethesda II (n=4), Bethesda III (n=2), Bethesda IV (n=25), Bethesda V (n=3) and Bethesda VI (n=1). On ultrasound most of the nodules were predominantly: solid (n=27), ovoid shape (n=33), longer than tall (n=33), with circumscribed margins (n=26), mixed vascularization (n=30) and heterogenous echotexture (n=15), mildly hypoechoic (n=16) or isoechoic (n=13). The stiffness of nodules was assessed in the strain elastography either Asteria score 2 (n=16) or 3 (n=11). On CEUS examination the majority of nodules presented contrast enhanced patterns (comparing with thyroid parenchyma) as: iso- or high, heterogenous and centripetal enhancement with fast or equal wash-in and wash-out. Most lesions were classified on ultrasound as low risk - EU-TIRADS-2 (n=13) or intermediate risk – EU-TIRADS-3 (n=15), but 7 lesions were assigned to EU-TIRADS-5 characterised as taller than wide (n=2), markedly hypoechoic (n=4) with circumscribed margins (n=2).

Conclusions: Preliminary results indicate that most ultrasound features are typical for benign tumors, but still 20% of lesions were assigned to EU-TIRADS-5 category. Despite the fact, that borderline nodules present indolent disease with minimal risk of recurrence, it should not be underestimated, and the proper management of patients should be introduced.