Objective: To compare preoperative fine needle aspiration biopsy (FNAB) and postoperative histopathological findings in patients undergoing thyroidectomy and to validate the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC).

Methods: Data from 366 patients who underwent thyroidectomy between 2014-2016 were analyzed retrospectively and the variables related to thyroid cancer were investigated.

Results: Of 366 patients, 44 (12%) were male and 322 (88%) were female. Regarding FNAB results according to TBSRTC, 23 (6.3%) patients had category I, 79 (21.6%) had category II, 128 (35%) had category III, 113 (30.9%) had category IV, nine (3.8%) patients had category V and 14 (2.5%) had category VI cytology. Histopathological examination revealed thyroid cancer in 65 (17.7%) patients. The Bethesda System was found to have a sensitivity of 73.9% and a specificity of 96%. There was no association between thyroid cancer and other variables except male gender.

Conclusion: Although TBSRTC has an acceptable sensitivity and specificity, the risk of malignancy in category III and IV patients may vary. Therefore, multidisciplinary approach should be considered during treatment planning and surgical treatment option should be kept in mind.