Endocrine Abstracts

JOINT3645

Introduction: Advancements in imaging techniques, particularly ultrasonography, have significantly improved the detection and characterization of thyroid nodules. The implementation of the EU-TIRADS classification system has standardized clinical practices, providing clear guidelines for fine-needle aspiration cytology (FNAC). Interpretation of FNAC using the Bethesda categories enables clinicians to decide between ultrasound surveillance and therapeutic intervention. However, discrepancies between imaging findings, cytological and histopathological results can pose diagnostic challenges, necessitating a multidisciplinary approach to ensure accurate diagnosis and appropriate management.

Case Presentations: Case 1: A 59-year-old female undergoing evaluation for chronic cough was found to have a heterogeneous macronodule in the left thyroid lobe on thoracic CT-scan, along with multiple nodules and micronodules present in both lung fields, osteolytic lesion affecting the body and right pedicle of the D3 vertebra with right paramedian and foraminal tumor-related epiduritis, likely of secondary origin. Cervical ultrasound confirmed the 56×34×40 mm EU-TIRADS IV nodule where fine-needle aspiration (FNA) classified it as Bethesda II. Calcitonin level was normal. Despite normal calcitonin level, the clinical context and suspicious imaging findings prompted total thyroidectomy. Histopathology revealed a conventional subtype papillary carcinoma (pT3aN1M1). Case 2: A 20-year-old female presented with dysphagia and a cervical swelling. Ultrasound identified a 15×8×14 mm right loboisthmic nodule (EU-TIRADS III) and a 5×3 mm left mediolobar nodule (EU-TIRADS III). FNA of the right nodule indicated a benign lesion (Bethesda II). Due to compressive symptoms, a right lobectomy was performed, revealing a 20 mm encapsulated variant of papillary carcinoma (pT1bN0). Subsequent left lobectomy identified a 3 mm follicular variant of papillary carcinoma with capsular invasion (pT1bNxMx). Initial thyroglobulin level was 7 ng/ml.

Discussion: The diagnostic evaluation of thyroid nodules aims to accurately identify malignancy while avoiding unnecessary interventions. However, discordance between imaging and cytological findings should prompt clinicians to pursue further investigations and engage in specialized multidisciplinary discussions to reach an appropriate therapeutic decision, ensuring thyroid neoplasms are not overlooked. Our study highlights the limitations of FNA in certain clinical scenarios and the potential of multifocal disease despite benign cytology.