Utility of fine-needle aspiration cytology and frozen-section examination in the operative management of thyroid nodules

Fine-needle aspiration cytology has a high sensitivity for the diagnosis of solitary thyroid nodules. Certain diagnoses involving follicular histologies often cannot be made with needle biopsy alone. The utility of frozen-section examination of thyroid nodules, with particular regard to those lesions with follicular histologies, is also limited. We examined the correlation of fine-needle aspiration cytology and frozen-section examination in solitary thyroid nodules to determine the contribution of frozen-section examination to the operation. We reviewed the fine-needle aspiration cytology, frozen-section examination, and final pathology of 100 consecutive patients undergoing thyroidectomy for a solitary solid thyroid nodule in an 4-year period. The diagnoses were classified as indeterminant, benign, or malignant. The utility and impact of the diagnosis from fine-needle aspiration or frozen section on the operative procedure performed was analyzed. Fine-needle aspiration cytology as a diagnostic test for thyroid nodules demonstrated an indeterminant rate of 23 per cent, with a diagnostic accuracy of 77 and 92 per cent for benign and malignant disease, respectively. In all patients with inaccurate benign diagnosis on fine-needle aspiration cytology, follicular neoplasm was misinterpreted for follicular adenoma or multinodular goiter. In comparing frozen-section results, the indeterminant, benign, and malignant rates were 7, 96, and 64 per cent, respectively. Of the 23 patients with indeterminant results on fine-needle aspiration cytology, the intraoperative frozen-section diagnosis on 4 patients was deferred to permanent section; 18 received accurate cytological diagnosis; and in 1 patient, carcinoma was missed. Overall, the decision about the extent of surgical thyroid resection was changed in only 2 patients based on the frozen-section results. Preoperative evaluation with fine-needle aspiration cytology can accurately and appropriately define the extent of thyroid surgery in most patients with a diagnosis of malignant neoplasm or benign disease. Intraoperative frozen-section examination may be helpful if fine-needle aspiration cytology results are inderminant and in cases of follicular histology as an adjunct for evaluation of the thyroid nodule, but overall, frozen section does not contribute to the management of the thyroid lesion at the time of surgery.