Thyroid fine-needle aspiration biopsy: progress, practice, and pitfalls.

OBJECTIVE: To provide an updated review of the current progress in, and the practice and pitfalls of, thyroid fine-needle aspiration (FNA) biopsy. METHODS: The medical literature on the topic was reviewed, and the current methods, advantages, and controversies concerning FNA biopsy of thyroid nodules are summarized. RESULTS: Thyroid nodules are a common clinical problem, with an estimated prevalence ranging from 19 to 35%. Most thyroid cancers manifest as thyroid nodules; however, only a small fraction of all thyroid nodules harbor malignant disease. Certain clinical features increase the likelihood of malignant involvement, but the absence of such features does not exclude the possibility of cancer. Of all currently available methods of evaluating nodular thyroid disease, FNA biopsy has been found to have the greatest diagnostic accuracy, approaching 95%, and its widespread use has resulted in substantial cost savings and has allowed a much better selection of patients in need of surgical treatment. The procedure, however, has two major limitations: nondiagnostic yield and indeterminate results. The approach to the management of patients with thyroid nodules is summarized. CONCLUSION: FNA is the most reliable and cost-effective method of distinguishing benign from suspicious or malignant thyroid nodules.