RESUMEN
INTRODUCTION: Indeterminate diagnoses are rendered on 15%-30% of thyroid fine-needle aspirates (FNA). Thus, a second diagnostic opinion given by an outside expert pathologist is a common practice that facilitates a more appropriate clinical management. Conversely, the role of an intra-institutional second opinion diagnosis (iSOD), which is usually informally performed in-house, has not been well established. METHODS: To assess the contribution of iSOD, a retrospective series of 34 thyroid FNA diagnosed as follicular neoplasm/suspicious follicular neoplasm (FN/SFN) with matched histological follow-up and a malignancy rate of 17.6% was selected and independently reviewed by two cytopathologists (CYT1 and 2). Cases with discrepant diagnoses were referred to a third in-house senior cytopathologist for the iSOD. The malignancy rates (MR) obtained after single independent reviews and iSOD were compared. RESULTS: MR obtained after CYT1 and CYT2 re-screening was similar (14.28% and 19.04%, respectively) and did not improve the original MR (17.64%). Conversely, after the iSOD of discrepant diagnoses, the overall malignancy rate increased up to the 27.27%, potentially sparing unnecessary surgical procedures. CONCLUSIONS: Intra-institutional second opinion practice for "indeterminate" thyroid FNA avoids unnecessary surgeries and maximises the detection of malignant cases diagnosed as FN/SFN.