Reliability of fine needle aspiration biopsy in large thyroid nodules

OBJECTIVE Fine needle aspiration biopsy provides one of the most important data that determines the treatment algorithm of thyroid nodules. Nevertheless, the reliability of fine needle aspiration biopsy is controversial in large nodules. The aim of this study was to evaluate the adequacy of fine needle aspiration biopsy in thyroid nodules that are four cm or greater. MATERIAL AND METHODS We retrospectively examined 219 patients files who underwent thyroidectomy for thyroid nodules that were greater than four centimeter between May 2007 and December 2012. Seventy-four patients with hyperthyroidism, and 18 patients without preoperative fine needle aspiration cytology were excluded from the study. Histopathologic results after thyroidectomy were compared with preoperative cytology results, and sensitivity and specificity rates were calculated. RESULTS False-negativity, sensitivity and specificity rates of fine needle aspiration biopsy of thyroid nodules were found to be 9.7%, 55.5%, and 85%, respectively. Within any nodule of the 127 patients, 28 (22.0%) had thyroid cancer. However, when only nodules of at least 4 cm were evaluated, thyroid cancer was detected in 22 (17.3%) patients. CONCLUSION In this study, fine needle aspiration biopsy of large thyroid nodules was found to have a high false-negativity rate. The limitations of fine-needle aspiration biopsy should be taken into consideration in treatment planning of thyroid nodules larger than four centimeters.