Background: Thyroid nodules are prevalent and mostly benign, being present in up to 67% of the population when assessed by ultrasound. Due to the variable diagnostic performance of ultrasound-guided fine-needle aspiration biopsy (USFNA) of the thyroid and the possibility of a false-negative result, current clinical guidelines recommend ultrasonographic follow-up of benign thyroid nodules. The objective of this study was to evaluate the clinical relevance of a repeat fine-needle aspiration (rFNA) in patients with an initial benign fine-needle aspiration biopsy (iFNA).
Methods: A retrospective review was conducted of medical records of patients seen at the Mayo Clinic between January of 2003 and December of 2013 who had undergone rFNA of a nodule with benign iFNA. The outcome measured was the result of the rFNA and histopathological correlation, when available.
Results: Three hundred and thirty-four nodules with benign iFNA underwent rFNA during the 10-year study period. The rFNA was most commonly reported as benign (85.3%), followed by suspicious (7.2%), nondiagnostic (5.7%), and malignant (1.8%). The rFNA changed clinical management in 9.5% of the cases. The prevalence of thyroid malignancy ranged from 4.1% to 1.2% based on the gold standard used (histology vs. long-term follow-up, 4.0 ± 2.3 years).
Conclusion: In the majority of patients with a benign iFNA, results of the rFNA were unchanged. However, in a small group of patients, the rFNA may differ from the initial results, and alter management. Even so, the prevalence of malignancy remains very low, ranging from 1.2% to 4.1% depending on the gold standard.