PURPOSE: To evaluate diagnostic value of core-needle biopsy (CNB) in thyroid nodules having nondiagnostic readings on previously fine-needle aspiration (FNA).
MATERIALS AND METHODS: From October 2008 to July 2011, 600 consecutive core-needle biopsies for thyroid nodules were performed. Among them 157 (median age, 52 years; age range, 22-76 years) thyroid nodules showed nondiagnostic reading in previous FNA were retrospectively reviewed. The Bethesda System for Reporting Thyroid Cytopathology was used for FNA and CNB readings. Malignant nodules (n = 37), were diagnosed after surgery. Benign nodules (n = 81) were diagnosed on histopathological readings after surgery, or benign cytology readings of FNAs and/or CNB that had been repeated at least two times or a benign readings of FNA or CNB with a stable size at follow-up. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of US-guided core-needle biopsy were calculated.
RESULTS: On CNB, one (0.6%) showed nondiagnostic reading and 19 nodules (12.1%) were inconclusive diagnoses (nondiagnostic and AUS/FLUS). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of core biopsy in detection of malignant were 94.6% (35 of 37), 100% (81 of 81), 100% (35/35), 97.6% (81/83) and 98.3% (116/118). The number of tissue cores obtained by CNB ranged from 1 to 3 (mean, 1.4)
CONCLUSION: US-guided core-needle biopsy of the thyroid nodule demonstrated a high conclusive diagnoses and accuracy in patients with previous nondiagnostic FNA reading.
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