Cost-effective evaluation of the patient with a thyroid nodule

Although thyroid nodules are common, less than 5% prove to be malignant. Because of its accuracy, simplicity, and low cost, FNAC has virtually replaced ultrasonography and radionuclide scintigraphy as the primary diagnostic procedure in the evaluation of the patient with a thyroid nodule. In studies comparing preoperative cytodiagnosis with histopathologic diagnosis, the predictive values of benign, malignant, and indeterminate cytodiagnoses averaged 94%, 96%, and 73%, respectively. Guidelines for a cost-effective approach to management of the patient with a thyroid nodule are presented. With a benign cytodiagnosis, follow-up with repeat FNAC in about 1 year is recommended. For the nodule with malignant or indeterminate cytology, surgical resection is indicated. Surgical resection is also indicated for the cyst that recurs after aspiration, as FNAC is less reliable owing to the paucity of cells. FNAC has less diagnostic utility in the evaluation of a nodule with clinical features suggesting malignancy, a nodule that is present in the diffuse toxic goiter of Graves' disease, or a nodule that is found in a patient with a history of radiation to the head, neck, or chest. In these circumstances, surgery is indicated irrespective of the cytologic findings.