Sonographic findings predictive of central lymph node metastasis in patients with papillary thyroid carcinoma: influence of associated chronic lymphocytic thyroiditis on the diagnostic performance of sonography.

ABSTRACT

OBJECTIVES: To analyze sonographic findings suggesting central lymph node metastasis of papillary thyroid carcinoma and to evaluate the influence of associated chronic lymphocytic thyroiditis on the diagnostic performance of sonography for predicting central lymph node metastasis. METHODS: A total of 124 patients (101 female and 23 male; mean age, 47.5 years; range, 21-74 years) underwent sonographically guided fine-needle aspiration in central lymph nodes from January 2008 to July 2011. Sonographic features of size, shape, margin, thickening of the cortex, cortical echogenicity, presence of a hilum, cystic changes, calcification, and vascularity of enlarged lymph nodes were analyzed before fine-needle aspiration and classified into 2 categories (probably benign and suspicious). Sonographic findings were correlated with the pathologic diagnosis and associated chronic lymphocytic thyroiditis. Receiver operating characteristic curve analysis was performed to assess the diagnostic performance of sonography for predicting central lymph node metastasis according to the associated thyroiditis. RESULTS: Fifty-one lymph nodes (39.5%) were malignant, and 73 (60.5%) were benign. On univariate analysis, size, shape, margin, cortical thickening, cortical echogenicity, cystic changes, calcification, and vascularity were significantly different between the benign and metastatic nodes (P < .05). On multivariate analysis, eccentric cortical thickening (odds ratio, 26.59; 95% confidence interval [CI], 3.26-216.66) and hyper echogenicity of the cortex (odds ratio, 18.46; 95% CI, 2.44-139.64) were significantly associated with malignant nodes (P < .05). The area under the curve values for sonography for predicting metastasis were 0.756 (95% CI, 0.618-0.894) in chronic lymphocytic thyroiditis-positive patients and 0.971 (95% CI, 0.938-1.000) in negative patients. CONCLUSIONS: Eccentric cortical thickening and cortical hyperechogenicity were the sonographic findings predictive of central lymph node metastasis from papillary thyroid carcinoma. The diagnostic performance of sonography for predicting metastasis was superior in chronic lymphocytic thyroiditis-negative patients than in positive patients.