Accuracy and consistency of fine-needle aspiration biopsy in the diagnosis and management of solitary thyroid nodules.

BACKGROUND Fine-needle aspiration biopsy has been well established as a diagnostic technique for selecting patients with thyroid nodules for surgical treatment, thereby reducing the number of unnecessary surgical procedures in cases of non-malignant tumors. OBJECTIVES To evaluate the sensitivity, specificity, accuracy, and positive and negative predictive values of FNAB in cases of a solitary thyroid nodule. METHODS The preoperative FNAB results in 170 patients who underwent thyroidectomy due to a solitary thyroid nodule were compared retrospectively with the final postoperative pathologic diagnoses. RESULTS In cases of a solitary thyroid nodule, FNAB had a sensitivity of 79%, specificity of 98.5%, accuracy of 87%, and positive and negative predictive values of 98.75% and 76.6% respectively. All cases of papillary carcinoma diagnosed by FNAB proved to be malignant on final histology, while 8 of 27 cases of follicular adenoma detected by preoperative FNAB were shown to be malignant on final evaluation of the surgical specimen. CONCLUSIONS FNAB cytology reduces the incidence of thyroidectomy since this method has excellent specificity and sensitivity and a low rate of false-negative results. It proved to be cost-effective and is recommended as the first tool in the diagnostic workup in patients with thyroid nodules.