Are scintigraphy and ultrasonography necessary before fine-needle aspiration cytology for thyroid nodules?

To evaluate the efficacy of scintigraphy, ultrasound and fine-needle aspiration in thyroid nodules and to establish the best diagnostic pathway in detecting thyroid cancer.

Two hundred and sixteen patients with thyroid nodules were examined using high-resolution ultrasonography, ^99mTc thyroid scintigraphy and ultrasound-guided fine-needle aspiration. Of these, 113 patients subsequently underwent thyroidectomy. The remaining 103 were followed up for two years without any evidence of malignancy.

Cytopathology classified 71% of the aspirate as benign, 3% as positive for malignancy, 21% as suspected neoplasia and 5% as unsatisfactory. Fine-needle aspiration cytology had a sensitivity of 87.5% and specificity of 80%. On ultrasound 33% of malignant nodules were hypo-echoic and on scintigraphy 16% of solitary cold nodules were malignant. Neither test could reliably diagnose thyroid cancer.

Ultrasound-guided fine-needle aspiration cytology should be the first test performed in euthyroid patients with a thyroid nodule. Scintigraphy and ultrasound imaging should be reserved for follow-up studies and patients who have suppressed levels of thyroid stimulating hormone.