Sonographic diagnosis of thyroid nodules: correlation with the results of sonographically guided fine-needle aspiration biopsy.

PURPOSE

To assess the reliability of sonography in differentiating benign from malignant thyroid nodules and selecting lesions for fine-needle aspiration (FNA).

METHODS

During a 2-year period, the following 7 sonographic parameters were assessed in 129 patients with thyroid nodules: size, number, echogenicity, echotexure, margin regularity, presence of calcifications, and presence of a hypoechoic rim. Sonographically guided FNA was performed on thyroid nodules 5 mm in diameter. Out of 184 FNAs, we obtained 168 specimens adequate for cytologic analysis and 16 (9%) nondiagnostic specimens.

RESULTS

FNA diagnoses included 150 (89%) benign and 18 (11%) malignant nodules. Among 53 solitary nodules, 11 were carcinomas and 42 were benign (p < 0.01). The mean size of the carcinomas was 28 +/- 12 mm versus 18 +/- 10 mm for benign nodules (p < 0.01). The following sonographic features were significantly associated with malignancy: hypoechogenicity, irregular margins, calcifications, and absence of a hypoechoic rim. Differences in echotexure between malignant and benign nodules were not statistically significant.

CONCLUSION

Sonographically guided FNA should be performed on thyroid nodules 5 mm in diameter with sonographic characteristics that suggest malignancy.