Micronuclei and nuclear buds: Highlighting overlooked indicators of chromosomal damage in thyroid aspiration smears

Abstract

Background: We aimed to examine the diagnostic utility of micronuclei (MN) and nuclear buds (NBs) in aspiration smears of the well-differentiated epithelial lesions of thyroid. Methods: One hundred five cases composed of 34 follicular nodular disease (FND), 31 Hashimoto's thyroiditis (HT), and 40 papillary thyroid carcinoma (PTC) were compiled retrospectively. MayGruunwald Giemsa (MGG) stained smears of each case were selected to count cells with nuclear protrusions (NPs) per 1000 cells. The frequency of cells with NPs (MN&NBs) was compared by using Mann-Whitney U test and Kruskal-Wallis tests when appropriate. Post-Hoc Tukey test was used for pairwise comparison of different diagnostic categories. By running a ROC curve analysis, diagnostic usefulness of the frequency of cells with NPs (MN&NBs) and their cut-off values to predict malignant behavior were calculated. P< 0.05 was regarded as significant. Results: NPs (MN&NBs) were significantly more frequent in malignant cases than benign ones. NBs were more frequent in conventional PTC compared to FV of PTC, but the frequency of MN did not significantly differ between these. ROC curve analysis revealed that evaluation of the frequency of cells with NPs (MN&NBs) was a highly specific, sensitive, and diagnostically useful method to identify malignant behavior. Conclusion: To the best of our knowledge, this is the first study in the literature to evaluate the frequency of cells with NPs (MN&NBs) in human thyroid aspiration smears. Our results show that evaluation of NPs (MN&NBs) may be a useful diagnostic tool to detect PTC in thyroid aspiration smears.