Fine Needle Aspiration Biopsy of Thyroid Nodules: Diagnostic Value, Technical Aspects, Analysis of Results

The goal of the study was to determine diagnostic value of fine needle aspiration biopsy (FNAB) in detection of malignant thyroid tumors based on retrospective analyses of 40696 FNAB of patients with thyroid nodules. Results. Comparison of the results of FNAB with postoperative histological examination data from 3004 patients revealed that the rate of false positive cytopathological results was 1.2% and the rate of false negative results was 1.8%. The sensitivity reached 99.67%. The specificity of FNAB when taking into account follicular lesions dropped to 16.29%, while leaving follicular lesions – 94.29%. Cytological results of 49609 FNAB of patients with thyroid nodules according to Bethesda system were arranged as follows: noninformative results – 8%, benign nodules – 81.9% (colloid nodules – 71.6%, autoimmune thyroiditis – 10.2%, subacute thyroiditis and others – 0.02%), follicular lesions – 7.2% (follicular neoplasm – 7.1%, follicular lesion of indeterminate value – 0.1%), suspicious for malignancy – 0.02%, malignant tumor – 3%, among the lat� ter papillary carcinoma – 93%. Malignant tumors, according to postoperative histological examination, were detected among the group with cyto� logical diagnosis “follicular neoplasm” in 16.3% of cases. After performing FNAB of regional lymph nodes with suspicious ultrasound signs the metastases of papillary carci� noma were revealed in 24.6% of cases. Application of FNAB in clinical practice at our Center to all patients with thyroid nodules of 1 cm in size and larg� er resulted in increment of thyroid operations for oncological indications from 12.5% in 2004 to 53% in 2012. Conclusion. FNAB under ultrasound control is the most informative differential method for thyroid diseases, per� mitting to reveal primary and metastatic thyroid lesions. FNAB allow to evade nonobligatory diagnostic operations in many patients.