Diagnostic accuracy of fine needle aspiration cytology in thyroid lesions

Purpose: evaluation of accuracy of fine needle aspiration cytology (fnac) in the diagnosis of different thyroid lesions. patients and methods: this is a retrospective study of 296 diagnosed cases of thyroid nodules referred to cytology unit,pathology department,nci,who underwent fnac for diagnosis. the results were categorized according to the recent bethesda classification into: insufficient for diagnosis,benign,atypical follicular lesion of undetermined significance,follicular neoplasm,suspicious for malignancy,and malignant sampling. the final histologic diagnosis and/or clinico-radiologic follow-up assessment for non-neoplastic lesions were considered the gold standard. results: the study included 296 cases presented with thyroid nodules who underwent diagnostic thyroid fnac. female to male ratio was 5.2:1,and the median age was 44. years. ninety-eight cases (33.1%) were diagnosed as benign,40 cases (13.5%) as follicular lesion of undetermined significance,49 cases (16.5%) as follicular neoplasm,30 cases (10.1%) as suspicious for malignancy,58 cases (19.5%) as malignant,and 21 cases (7.1%) as unsatisfactory. nodular hyperplasia represented the majority of benign cases (89.8%),while papillary carcinoma was the most frequent malignant lesion (72.4%). cytologic diagnoses were compared with their corresponding final histologic ones. fnac achieved a sensitivity of 92.8,a specificity of 94.2%,a positive predictive value of 94.9%,a negative predictive value of 91.8%,a false positive rate of 7.2%,a false negative rate of 5.8%,and a total accuracy of 93.6%. conclusion: fna cytology is a sensitive,specific,and accurate initial diagnostic test for the evaluation of patients with thyroid swellings. © 2012 national cancer institute,cairo university.