Cytohistological correlation of thyroid fine-needle aspiration cytology with emphasis on discordant cases: A tertiary care center study

CONTEXT: Fine-needle aspiration (FNA) is a reliable, most noninvasive, cheap, and efficient procedure to differentiate between benign and malignant thyroid nodules.[1] The six proposed Bethesda categories are known to reduce the “gray zone” in thyroid FNA that can be due to the nature of the aspirates and the level of experience of cytopathologists.[2] AIM: This study was aimed at finding the causes for cytohistological discordance, thereby minimizing the false-positive (FP) and false-negative (FN) results. SETTINGS AND DESIGN: This was a retrospective study of FNA cytology of thyroid nodules with histopathological findings on subsequent surgical resection and their correlation with emphasis on discordant cases. SUBJECTS AND METHODS: A total of 568 patients with thyroid swelling were aspirated during the 3-year study. Histopathological diagnoses were available in 288 cases, out of which 32 cases were discordant. Cases showing cytohistological disparity were re-evaluated. STATISTICAL ANALYSIS USED: The statistical analysis method used was the Chi-square test. Sensitivity, specificity, positive predictive value, negative predictive value, FP, FN, accuracy, and discrepancy rates were measured. RESULTS: Cytohistological concordance was achieved in 88.9% of the cases. Of the discordant cases, FN cases accounted for 9.4% and FP for 1.7%. CONCLUSIONS: Proper representative sampling, if needed to be guided by imaging modalities and meticulous examination of all the smears are the key points in reducing the number of discrepant cases.