Sonographic characteristics suggesting papillary thyroid carcinoma according to nodule size

Abstract

PURPOSE: To evaluate differences in sonographic features suggesting papillary thyroid cancer (PTC) according to nodule size.MATERIALS AND METHODS: We included 1238 nodules in 1173 patients that were confirmed through cytology or surgery between February 2007 and June 2007 in the study. All thyroid malignancies were diagnosed as PTC. Nodules were divided into two groups: 571 lesions >10 mm in size (large lesions) and 667 lesions ≤10 mm in size (small lesions). Sonographic features were defined as composition, echogenicity, margin, calcifications, shape, and vascularity. Logistic regression analyses were performed to assess the relevance of sonographic features to the prediction of PTC by determination of odds ratios (OR).RESULTS: Significant features for malignancy in both groups were solid composition, hypoechogenicity, marked hypoechogenicity, microlobulated margin, irregular margin, microcalcification, and taller than wide shape. In large lesions, irregular margin (OR: 40.372), microcalcifications (OR: 37.512), marked hypoechogenicity (OR: 17.069), microlobulated margin (OR: 10.918), solid composition (OR: 7.082), taller than wide shape (OR: 6.077), hypoechogenicity (OR: 2.389), and lack of vascularity (OR: 2.341) increased the risk of malignancy. In small lesions, irregular margin (OR: 8.941), taller than wide shape (OR: 7.997), microlobulated margin (OR: 6.244), marked hypoechogenicity (OR: 6.091), solid composition (OR: 5.773), microcalcifications (OR: 5.249), and hypoechogenicity (OR: 1.610) were strongly associated with PTC.CONCLUSIONS: Our study demonstrated that the OR of each US finding for predicting PTC is different according to nodule size and provided a rationale for weighting certain US features when reporting thyroid nodules with different risks of PTC according to nodule size.