Thyroid follicular neoplasm diagnosed by US-guided core needle biopsy: correlation with surgical histology

Abstract

OBJECTIVE The purpose of this study was to evaluate the outcome of US-guided CNB in the diagnosis of thyroid follicular neoplasms with surgical histology as the reference standard. MATERIALS AND METHODS Between January 2011 and February 2014, a total of 133 patients underwent gray-scale US and subsequent US-guided CNB because of indeterminate or inadequate cytology. Patients were only included if they then underwent thyroid surgery for a histologic diagnosis on CNB of a follicular neoplasm (FN) (n=13) or a suspicious follicular neoplasm (SFN) (n=3). The patients comprised 13 women and 3 men with a median age of 50 years (range, 19 to 64 years). The mean diameter of the 16 thyroid nodules was 27.6 mm (range, 6 to 73 mm). The US images and pathologic reports of these patients after FNA, CNB and surgery were retrospectively reviewed. The malignancy rate of these patients was evaluated and the rate was compared between the FN group and the SFN group. RESULTS Of the 16 cases that underwent surgery, eight (50%) cases were confirmed to be a malignancy on the surgical histologic results. Surgical histology revealed 11 (68.8%) follicular neoplasms with six follicular carcinomas (6/11, 54.5%) and five follicular adenomas (5/11, 45.5%). The other histologic types were papillary carcinoma (n=1), medullary carcinoma (n=1), and adenomatous hyperplasia (n=1). The malignancy rate of the FN group was 76.9% and that of the SFN group was 33.3%. There was no difference in the malignancy rate between the FN or SFN group (p>0.05). CONCLUSION When US-guided CNB suggested a follicular neoplasm, the histologic diagnosis was confirmed based on surgical histology in 50% of cases. US-guided CNB could be useful for the preoperative identification of thyroid FNs.