No abstract

Ultrasonography is the main imaging method for the workup of thyroid nodules. However, interobserver agreement reported for echogenicity and echotexture is quite low. The aim of this study was to perform quantitative measurements of the degree of echogenicity and heterogeneity of thyroid nodules, to develop an objective and reproducible method to stratify these features to predict malignancy.A retrospective study of patients undergoing ultrasonography-guided fine-needle aspiration was performed in an University hospital thyroid center. From January 2010 to October 2012, 839 consecutive patients (908 nodules) underwent US-guided fine-needle aspiration. In a single ultrasound image, 3 regions of interest (ROIs) were drawn: the first including the nodule; the second including a portion of the adjacent thyroid parenchyma; the third, the strap muscle. Histogram analysis was performed, expressing the median, mean, and SD of the gray levels of the pixels comprising each region. Echogenicity was expressed as a ratio: the nodule/parenchyma, the nodule/muscle, and parenchyma/muscle median gray ratios were calculated. The heterogeneity index (HI) was calculated as the coefficient of variation of gray histogram for each of the 3 ROIs. Cytology and histology reports were recorded.Nodule/parenchyma median gray ratio was significantly lower (more hypoechoic) in nodules found to be malignant (0.45 vs 0.61; P = 0.002) and can be used as a continuous measure of hypoechogenicity (odds ratio [OR] 0.12; 95% confidence interval [CI] 0.03–0.49). Using a cutoff derived from ROC curve analysis (<0.46), it showed a substantial inter-rater agreement (k = 0.74), sensitivity of 56.7% (95% CI 37.4–74.5%), specificity of 72.0% (67.8–75.9%), positive likelihood ratio (LR) of 2.023 (1.434–2.852), and negative LR of 0.602 (0.398–0.910) in predicting malignancy (diagnostic odds ratio 3.36; 1.59–7.10). Parenchymal HI was associated with anti-thyroperoxidase positivity (OR 19.69; 3.69–105.23). The nodule HI was significantly higher in malignant nodules (0.73 vs 0.63; P = 0.03) and, if above the 0.60 cutoff, showed sensitivity of 76.7% (57.7–90.1%), specificity of 46.8% (42.3–51.4%), positive LR of 1.442 (1.164–1.786), and negative LR of 0.498 (0.259–0.960).Evaluation of nodule echogenicity and echotexture according to a numerical estimate (nodule/parenchyma median gray ratio and nodule HI) allows for an objective stratification of nodule echogenicity and internal structure.

Results from national cancer registries reveal an association of thyroid cancers with extra-thyroidal malignancies. In this study, we evaluated the prevalence of breast cancer (BC) in women affected by both benign and malignant thyroid diseases (TD) in comparison to the general population. To this end, 3,921 female patients from central and southern regions of Italy were evaluated. Age-matched analysis of the prevalence of BC was carried out after dividing the patients into three diagnostic categories: (1) 1,149 patients with non-nodular TD; (2) 2350 patients with nodular TD; (3) 422 patients affected by differentiated thyroid cancers. Furthermore, the patients were grouped according to the absence (2,344 patients) or presence (1,453 patients) of anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase (TPOAb) or anti-TSH receptor auto-antibodies (124 patients). BC prevalence in TD patients as a whole was significantly higher compared to the general population, with an odds ratio (OR) of 3.33. Age-matched analysis showed that the risk of a BC in TD patients was higher in younger patients (age 0-44 years), with an OR of 15.24, which decreased with increasing age. Patients without thyroid auto-antibodies showed a higher OR for BC (p = 0.0005) than TD patients with TgAb and/or TPOAb. The results demonstrate that women affected by either benign or malignant thyroid disease have a significantly greater risk of BC, which is higher at a younger age. Furthermore, thyroid auto-antibodies appear to be protective against BC. These findings may contribute to the identification of common genetic and environmental factors underlying this disease association.