Abstract

<p>Thyroid nodules are a common clinical finding, with an estimated 4-7% of adults presenting with palpable nodules, and up to 60% of individuals over 60 years old showing nodules on ultrasound screening. While most thyroid nodules are benign, a significant percentage (5-15%) are malignant, making accurate diagnosis critical. The most common malignancies include papillary thyroid carcinoma, follicular carcinoma, and medullary carcinoma, with papillary carcinoma being the most prevalent. Fine Needle Aspiration Cytology (FNAC) is widely regarded as the first-line diagnostic tool for thyroid nodules due to its minimally invasive approach, cost-effectiveness, and high diagnostic accuracy. FNAC involves aspirating cells from the nodule, which are then examined microscopically, with results classified according to the Bethesda System for Reporting Thyroid Cytopathology. This system divides results into six categories: nondiagnostic/unsatisfactory, benign, atypia of undetermined significance (AUS), suspicious for follicular neoplasm, suspicious for malignancy, and malignant, helping guide clinical management decisions. Despite its widespread use, FNAC has limitations, including uncertainty in cases with AUS or suspected follicular neoplasm, and false-negative or false-positive results. As a result, histopathological examination after thyroidectomy remains the gold standard for definitive diagnosis, offering a comprehensive assessment of the nodule's cellular and molecular characteristics. This review highlights the diagnostic utility of FNAC in thyroid nodule evaluation, its limitations, and the complementary role of histopathology in ensuring accurate diagnosis and appropriate patient management</p>