Ultrasound guided fine-needle aspiration biopsy of thyroid nodules: Guidelines and recommendations vs clinical practice; a 12-month study of 89 patients

Given the high prevalence of thyroid nodules in the general population it is essential to develop a method for identifying those nodules which require fine-needle aspiration biopsy (FNAB) due to suspicion for malignancy in order to avoid over- or under treatment of this disease. The ultrasound (US) criteria identified by Kim et al. and the American Association of Clinical Endocrinologists appear to be the most sensitive and most specific. The purpose of this study was to analyze a sample of patients who underwent FNAB of the thyroid and to compare the obtained data with the international guidelines and the recommendations for management of thyroid nodules.

This study analyzed the clinical, anamnestic and US reasons for which 97 nodules located in 89 patients underwent FNAB, and the data were compared with the criteria set by the guidelines and with the cytological results.

Echogenicity was indication for FNAB in 99% of cases, appearance of the margins in 75.3%, presence of calcifications in 93.8% and presence of vascularity in 73.2%. In a total of 4.1% of cases, cytological outcome was positive for malignancy, 21.6% necessitated monitoring, 4.1% were referred to surgery and histological examination of the surgical specimen and 63.9% resulted negative for malignancy.

The finding of hypoechoic nodules often leads to continued investigation; the presence of intranodular vascularization detected at Doppler US is perceived as suspicious and the presence of microcalcifications always leads to further investigation. On the request of the endocrinologist the dominant nodule in a goiter is in most cases subjected to FNAB even if the volume has not increased. Adequate US criteria can help identify potentially malignant nodules and guide implementation of FNAB. However, identification of malignant nodules using instrumental investigation cannot disregard medical records and clinical laboratory tests. According to the authors' experience, a close collaboration between endocrinologists, radiologists and pathologists is essential for a correct evaluation of patients with thyroid nodules in order to avoid over or under estimation of the risk of malignancy of a nodule and therefore of the necessity to perform further examinations.