Hamadan University of Medical Sciences Journal of Research in Health Sciences 2228-7795 25 3 2025 06 10 Diagnostic Value of Fine Needle Aspiration in Diagnosis of Thyroid Nodules at the Endocrine Clinic of Hamadan City During a 10-Year Period, Iran e00658 e00658 10.34172/jrhs.7768 EN Mahsa Zamiri Mofid https://orcid.org/0000-0002-2658-7466 Erfan Ayubi https://orcid.org/0000-0002-8829-9304 Aidin Tarokhian Shiva Borzouei https://orcid.org/0000-0001-6826-9872 Journal Article 10.34172/jrhs.7768 2024 11 08 2025 02 28 Background: Thyroid nodules are common endocrine disorders. Most nodules are benign, with only 5% to 15% being malignant. Fine needle aspiration (FNA) is a primary diagnostic method; however, recent studies have raised concerns about its diagnostic reliability. This study aimed to evaluate performance of FNA in diagnosing thyroid nodules using pathology results as the gold standard. Study Design: A cross-sectional study. Methods: This study analyzed patients who were referred to an endocrine clinic in Hamadan city and underwent thyroidectomy during a 10-year period. The collected data included demographics, clinical symptoms, FNA results, and pathological outcomes. Statistical analysis was conducted using Stata software, with the significance level set at 0.05. Results: The study included 700 patients, predominantly female (86.2%), with a mean age of 42.5 years. FNA results were as follows: non-diagnostic in 4.8% (n=43), benign in 43.4% (n=304), atypia of undetermined significance or follicular lesion of undetermined significance in 6.1% (n=42), follicular neoplasm in 13.2% (n=92), suspicious for malignancy in 22.8% (n=160), and malignant nodules in 9.7% (n=68) of the cases. Pathology revealed malignant nodules in 56.9% (n=398) of the cases, predominantly papillary carcinoma. Significant factors associated with malignancy included younger age, male gender, history of thyroid cancer in a first-degree relative, and the presence of cervical adenopathy. FNA showed a sensitivity of 72.43% (95% CI 67.58%, 76.93%) and a specificity of 89.64% (95% CI 85.46%, 92.95%), with an accuracy of 79.85% (95% CI 76.55%, 82.87%). Conclusion: While FNA is a valuable diagnostic tool for thyroid nodules, its sensitivity varies, necessitating close follow-up of patients with negative results.