Abstract
Thyroid nodules occur frequently, and ultrasonography and cytological examinations are the standard methods for evaluating the characteristics of thyroid nodules and determining the indications for surgery. Although several reports have evaluated the accuracy of ultrasonographic or cytological examinations in detecting malignant thyroid tumors, their accuracy is not high enough, and inadequate diagnosis may cause delayed treatment of malignant tumors. Therefore, we combined the ultrasonographic and cytological findings and established a new surgical criterion to improve the accuracy of the preoperative detection of malignant tumors. The results of ultrasonography and cytological and histological diagnosis of 191 cases of resected thyroid tumors were retrospectively analyzed.
Ultrasonography findings were assessed for microcalcifications, irregular tumor margins, and high intratumoral blood flow; cytological findings were categorized into six types based on the Bethesda classification; and the histological diagnosis was classified into malignant and non-malignant.
Statistical analysis revealed that intratumoral microcalcifications and irregular tumor margins were characteristic ultrasonography features indicating the possibility of malignant tumors (p < 0.05). A combination of ultrasonographic and cytological findings, Bethesda classification V (suspicious for malignancy), VI (malignant), or I-IV with either intratumoral microcalcifications or irregular margins of the tumor, could be used to preoperatively identify malignant tumors with a relatively high accuracy (sensitivity, 93.4%; specificity, 71.0%; area under the curve [AUC], 0.822 [95% confidence interval: 0.753-0.892]). Our new surgical indication showed higher sensitivity and AUC than previous surgical indications based only on the Bethesda classification in cytological examinations.
