Correlation between thyroid fine needle aspiration cytology and postoperative final histopathology: a 5-year single-centre retrospective study

Abstract

Background: Thyroid nodules are common problems encountered in our routine practice. Fine needle aspiration cytology (FNAC) is the most accurate and cost-effective method for evaluating thyroid nodules. It is the procedure of choice for identifying patients who require surgical excision. Methods: This is a retrospective single-center observational study in Salmaniya Medical Complex, a tertiary care center, in Kingdom of Bahrain that aims to to correlate preoperative FNAC results with the post-surgical histopathology report, and to compare our diagnostic performance results to previously published literature. Results: The post-operative histology was reported as benign in 62% of patients and malignant in 38% of patients. Bethesda II was the most common category in our sample, with 14.3% having a final histopathological diagnosis of malignancy (false negative results). Malignancy was found in 84% and 96.8% of Bethesda V and VI, respectively. Our FNAC data achieved an 80.95% sensitivity, specificity of 93.51% specificity, and a total accuracy of 87.86%. The positive predictive value was 91.07%, and an 85.71% negative predictive value, which were comparable to data from published series. Conclusions: FNAC remains the most accurate and cost-effective method for evaluating thyroid nodules. However, its diagnostic value varies among different institutions. Our results demonstrated higher rates of malignancy compared to other published series in both category I and II. Due to the chance of false negative rates in these categories and the slow-growing nature of thyroid malignancy, it is important that patients with benign FNAC should have periodic clinical and radiological follow up.