DIAGNOSTIC VALUE OF FINE-NEEDLE ASPIRATION BIOPSY IN PATIENTS WITH THYROID CANCER AND HASHIMOTO THYROIDITIS

Abstract

Introduction: Thyroid nodules are a common finding in clinical practice, with prevalence ranging from 2-6% on physical examination, 19–35% on ultrasound, and 8–65% in autopsy studies. Their incidence increases with age and is more frequent in women, individuals with iodine deficiency, and those previously exposed to ionizing radiation. Hashimoto’s thyroiditis may alter cytological interpretation and affect diagnostic accuracy. Methods: This retrospective study included 80 patients with thyroid nodules and Hashimoto’s thyroiditis who underwent fine-needle aspiration biopsy (FNAB), followed by surgical thyroid resection. Diagnostic accuracy parameters were calculated based on histopathological findings as the reference standard. Results: FNAB demonstrated high sensitivity, indicating effective detection of malignant lesions. The positive predictive value was 100%, confirming the strong reliability of FNAB in identifying malignancy when cytology is positive. However, false-negative results occurred predominantly in Bethesda categories I and II. Conclusion: FNAB remains a key and highly accurate preoperative diagnostic method for evaluating thyroid nodules. The exceptionally high positive predictive value supports its diagnostic strength. Nevertheless, the presence of false-negative cases underscores the need for close clinical and ultrasound follow-up in patients with benign cytology, particularly due to the possibility of microcarcinoma or slow-growing thyroid carcinoma.