Examination of Malignant Findings of Thyroid Nodules Using Thyroid Ultrasonography

Background It is important to distinguish benign thyroid nodules from malignant thyroid nodules. Hence, this study aimed to determine the characteristics of patients with thyroid cancer using thyroid ultrasonography. Methods We retrospectively examined the ultrasonographic findings of 327 patients with 457 thyroid nodules (age: 59.9 ± 14.3 years; sex, n (%): female 242 (74.0%)) at a single center from 2014 to 2016. Ultrasonography was used to determine the nodule size, shape, border, internal echogenicity, presence of coarse calcifications and microcalcifications within the nodule, internal blood flow and whether the nodule was solid or contained cystic structures. Thyroid fine needle aspiration cytology (FNAC) was performed in all patients. The ultrasonographic findings were compared between patients with benign nodules and those with papillary thyroid carcinoma (PTC). Furthermore, in the analysis of anti-thyroglobulin (Tg) antibody-negative patients with single nodules, values of serum Tg/nodule volume were calculated and compared between patients with benign nodules and those with PTC. Results There were 298 (65.2%) benign nodules, 33 (7.2%) PTCs and 126 (27.6%) others (104 follicular neoplasms, 19 masses of undetermined significance and three other malignant tumors). The nodules diagnosed as PTC had significantly lower internal echogenicity (P < 0.01), more microcalcifications (P < 0.01) and comprised more nodules rich in blood flow (P < 0.05) than benign nodules. Solid nodules were found significantly more in the PTC group (P < 0.01). The serum Tg/nodule volume ratio was significantly higher in the PTC group (P < 0.05). Conclusions Findings suggestive of PTC were found from images obtained using thyroid ultrasonography. In the diagnosis of PTC, the frequency of FNAC examinations should be reduced as this method is costly and invasive.