Contribution of high-resolution ultrasonography in the differential diagnosis of benign from malignant thyroid nodules.

The purpose of this study was to investigate the value of "high-resolution ultrasonography" in the differential diagnosis of benign from malignant thyroid nodules. The study included ultrasonography examination of 77 patients with thyroid nodules, who underwent thyroidectomy. The histological findings were subsequently compared with pre-operative sonographic findings. Thirty patients had malignant nodules and 47 patients had benign nodules. The sonographic features that were studied were: hypoechogenicity or isoechogenicity of the nodules, the presence of peripheral halo, the regular or irregular contour, the presence of microcalcifications, the presence of cystic degeneration and the existence of solitary or multiple nodules. The results revealed that low echogenicity constitutes a sonographic feature of malignancy with high sensitivity and medium specificity. The presence of microcalcifications is a feature of malignancy with low sensitivity but high specificity. Conversely, the regular contour of a nodule and the presence of peripheral halo are features of benign nodule with high sensitivity and specificity. Cystic degeneration occurs at the same rate in benign and malignant nodules. Solitary nodules were malignant more often than were multiple nodules, a finding that was not, however, statistically significant. We conclude that high-resolution ultrasonography contributes greatly in the preoperative differential diagnosis of thyroid nodules. It constitutes an important diagnostic means complementary to needle biopsy in the management of thyroid nodules and it is even more valuable in those nodules that cannot undergo biopsy.