ESPE Abstracts

Introduction: The risk of malignancy of pediatric thyroid nodules is determined according to the Bethesda System. Biopsy is performed by fine needle aspiration (FNA) based on ultrasonography (US) patterns. To identify suspicious nodules in adults, the Thyroid Imaging Reporting and Data System (TI-RADS) is widely used; however, its use in pediatrics is less common.

Aim: To analyze the usefulness of the Bethesda system and TIRADS to determine malignancy in pediatric patients with a single thyroid nodule.

Materialy Methods: The medical records of all patients ≤ 18 years who underwent thyroid FNA at our institution between December 2013 and December 2023 were retrospectively reviewed. Data on demographics, US characteristics, FNA cytology, histopathological findings, and ancillary data were assessed.

Results: Ninety-three patients were included (67% females). The median age at presentation was 13 years (4-18). The malignancy rate was 30.1%. According to the Bethesda System, the malignancy rate was 5.8% for category I (n:14), 4.4% for category II (n:46), 57 % for category III (n:14), 50% for category IV (n:2), 88% for category V (n:9), and 100% for category VI (n:8). In 25 patients with an indeterminate Bethesda category (categories III, IV and V), the malignancy rates according to TIRADS were 0% for TIRADS 2, 50% for TIRADS 3, 66.7% for TIRADS 4, and 100% for TIRADS 5. The US characteristics of the TIRADS score were analyzed separately in 57 patients in whom the corresponding histopathological findings were available. A higher prevalence of malignancy was associated with irregular margins (87.5%, χ² p:0.0002), calcifications (84.2%, χ² p:0.0002), and a solid composition (59.2%, χ² P = 0.0086).

Conclusion: In this cohort, we observed that the rate of pediatric thyroid malignancy for Bethesda system category III was higher than that reported in the literature. In the patients with an indeterminate Bethesda category and malignancy, the TIRADS score was ≥ 3. The presence of solid composition, irregular margins, and calcifications was associated with a high probability of thyroid nodule malignancy.