Diagnostic accuracy of circulating thyrotropin receptor messenger RNA combined with neck ultrasonography in patients with Bethesda III-V thyroid cytology.

Background. The aim of this study was to analyze the usefulness of thyrotropin receptor messenger RNA (TSHR-mRNA) combined with neck ultrasonography (US) in the management of thyroid nodules with Bethesda III-V cytology. Methods. Cytology slides of patients with a preoperative fine needle aspiration (FNA) and TSHR-mRNA who underwent thyroidectomy between 2002 and 2011 were recategarized based on the Bethesda classification. Results of thyroid FNA, TSHR-mRNA, and US were compared. with the final pathology. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results. There were 12 patients with Bethesda III, 112 with Bethesda IV, and 58 with Bethesda V cytology. The sensitivity of TSHR-mRNA in predicting cancer was 33%, 65%, and 79 %, and specificity was 67%, 66%, and 71%, for Bethesda III, IV, and V categories, respectively. For the same categories, the PPV of TSHR-mRNA was 25%, 33%, and 79%, respectively; whereas the NPV was 75%, 88%, and 71%, respectively. The addition of neck US to TSHR-mRNA increased the NPV to 100% for Bethesda III, and 86%, for Bethesda IV, and 82% for Bethesda V disease. Conclusion. This study documents the potential usefulness of TSHR-mRNA for thyroid nodules with Bethesda III-V FNA categories. TSHR-mRNA may be used to exclude Bethesda IV disease. A large sample analysis is needed to determine its accuracy for Bethesda category III nodules.