[ study of 450 cases of thyroid nodules and evaluation of diagnostic accuracy of fine needle aspiration]

ABSTRACT

Thyroid nodule is a common disease and although usually benign, malignancy should always be ruled out. Fine needle aspiration [FNA] is the diagnostic modality of choice in approach to thyroid nodules. The main aim of this study is assessment of characteristics of thyroid nodules, risk of malignancy and accuracy rate of FNA in patients in Mashhad. We studied 450 patients with thyroid nodules during 2003 through 2007 with physical examination, radioisotope scan and FNA. Thyroid surgery performed in 64 patients and histopathology results compared with FNA cytological results. The patients were 383 women [85.1%] and 67women [14.9%] with mean age of 39.8 +/- 12.7 years. The mean length of largest diameter of nodules was 3.97 +/- 1.8 and the smallest one was 3.26 +/- 1.7 [cm]. 59% of nodules were located on right lobe, 36% of them on left lobe and 5% on isthmus of thyroid. 24.4% of nodules were cystic. 30.3% of thyroid nodules were functional or hot and 69.7% of them were cold in thyroid radioisotope scan. In evaluation of cytological findings of nodules aspirate, 288 [68.6%] were benign, 22[5.2%] were malignant, 92 [21.9%] were follicular lesions, 13[3%] were suspicious and 5[%1.2] were non diagnostic. Comparison of cytopathologic results before and after surgery showed that FNA in operated patients yielded a sensitivity of 82. 3%, specificity of 78. 9%, a positive predictive value of 77.7%, negative predictive value of 83. 3% and accuracy of 80.5%