Thyroid Nodules with Initially Nondiagnostic Cytologic Results: The Role of Core-Needle Biopsy

Abstract

PURPOSE: To evaluate the role of core-needle biopsy (CNB) in thyroid nodules with nondiagnostic results at previous fine-needle aspiration (FNA). MATERIALS AND METHODS: From October 2008 to July 2011, 155 nodules from 155 patients (37 men, 118 women) with a mean age of 51.8 years (age range, 22-76 years) with nondiagnostic results at previous FNA were reviewed retrospectively. The Bethesda system for reporting thyroid cytopathologic results was used to assign FNA and CNB findings. Malignant nodules (n = 37) were diagnosed after surgery. Benign nodules (n = 79) were diagnosed either after surgery, with benign findings after FNA and/or CNB that had been repeated at least twice, or after benign cytology findings at FNA or CNB with a stable size at follow-up. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasonographically guided CNB were evaluated. RESULTS: At CNB, two nodules (1.3%) showed nondiagnostic results, and 135 nodules (87.1%) had conclusive diagnoses. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of core biopsies for the detection of malignancy were 94.6% (35 of 37), 100% (79 of 79), 100% (35 of 35), 97.5% (79 of 81), and 98.3% (114 of 116), respectively. For 28 nodules, nondiagnostic results were found after two or more FNA procedures; however, diagnostic surgery was performed in only one patient. CONCLUSION: CNB of the thyroid nodule demonstrates high rates of conclusive and accurate diagnoses in patients for whom previous FNA results were nondiagnostic, thereby reducing the need for unnecessary diagnostic surgery.