The Values of Fine Needle Aspiration and Needle Biopsy in the Diagnosis of Thyroid Nodules

Thyroid nodule is a common clinical problem and it is important to distinguish benign from malignant nodule. Although features found on history taking, physical examnation and imaging studies help the diagnosis, fine needle aspiration(FNA) has been accepted as an accurate and reliable diagnostic procedure of thyroid nodule. This study was aimed to assess the values of FNA and needle biopsy in the diagnosis of thyroid nodules.

We reviewed the medical records of the 405 patients who underwent FNA and needle biopsy for the diagnosis of thyroid nodule form September 1993 to July 1996.

The 414 fine needle aspiration cytologic specimens were obtained from 405 patients(male : 26, female : 379). 390 cases(94.2%) were adequate for cytologic diagnosis. And the diagnosis showed benign in 357(91.5%), malignancy in 20(5.1%) and suspicious malignancy in 13(3.3%). Among the 357 benign cases, 104 cases were benign cysts, 163 cases were adenomatous goiter and 45 cases were follicular adenoma. 46 patients underwent thyroidectomy after FNA and 21 patients(45.7%) were diagnosed as having carcinoma. The sensitivity and specificity of FNA in diagnosing malignancy were 65% and 82%, respectively, with an accuracy of 74%. Of 46 patients, needle biopsy was done in 41. The sensitivity and specificity of the needle biopsy were 79% and 73%, respectively. And the accuracy was 76%. Hoarseness was developed in one patient after FNA and needle biopsy, and small amount of hemoptysis was developed in another patient after FNA.

Although it had been expected that needle biopsy may increase the diagnostic accuracy, our study didn't show the superiority of needle biopsy as compared with FNA. FNA has limitations in suspicious and nondiagnostic results but it is a safe, simple, reliable and cost-effective means of evaluating thyroid nodules. It is the preferred initial diagnostic method in all patients with thyroid nodule.