Ultrasonography-Guided Fine Needle Aspiration of Incidentally Detected Nonpalpable Thyroid Nodule / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: With the availability of more sensitive ultrasonography, a larger number of nonpalpable thyroid nodule can be detected. But it is controversial that USG-FNA should be routinely used to incidentally detect nonpalpable thyroid nodule. The purpose of this study is to investigate the clinical significance of thyroid incidentaloma and the usefulness of the USG-FNA in the management of thyroid incidentaloma. SUBJECTS AND METHOD: A retrospective study was performed on 208 patients who underwent USG-FNA for thyroid incidentaloma smaller than 1.5 cm from 2001 to 2005. The cytologic findings were compared with the ultrasonographic findings and the surgical pathology. RESULTS: Suspicious malignant sonographic findings were detected in 48 cases. And in 10 cases, more than two malignant findings were detected. Of the 208 cases, 159 cases were cytologically diagnosed as benign lesion (76.4%), 7 cases as follicular neoplasm (3.3%), 33 cases as malignancy (15.8%), and 9 cases as inadequate specimen (4.4%). Of the 40 cases with follicular neoplasm and malignant cytology, 37 cases underwent surgery and 30 cases were confirmed to malignancy on the postoperative pathologic diagnosis. In the cases diagnosed to malignancy on pathology, extracapsular extension was present in 9 cases (30%), and nodal metastasis in 8 cases (26.7%). The sensitivity, specificity, and accuracy of the USG-FNA for malignancy were 93.3%, 71.4%, and 89.1%, respectively. CONCLUSION: USG-FNA is a useful diagnostic tool in the management of thyroid incidentaloma especially when more than two suspicious malignant sonographic findings need to be detected. The clinical characteristics is not significantly different between palpable and nonpalpable nodules.