Hyper-Echoic Rim in Thyroid Nodules: A New Ultrasonographic Feature for Malignancy Prediction

The goal of this study was to verify the ultrasound features of hyper-echoic rims in thyroid nodules and to evaluate their diagnostic value in predicting thyroid malignancies. We retrospectively analyzed 228 pathologically proven thyroid nodules (137 malignant and 91 benign nodules). Forty-eight thyroid nodules had a hyper echogenic rim. All malignant nodules (137) were papillary carcinomas, which were studied to identify the correlation between the hyper-echoic rim (detected by ultrasound) and other histologic features. Presence of a hyper-echoic rim had high specificity (94.51%), but low sensitivity (31.39%) in predicting malignancy (p < 0.05). Thirty-seven of 43 malignant nodules had boundary zones of mixed structure (apparent fibrous stroma bands or dense collagenous border with a mixed population of cancerous cells) under microscopic examination. In conclusion, the hyper-echogenic rim could be one additional ultrasound parameter in the diagnosis of thyroid lesions.