Potential Utility of Micronucleus and Binucleus Frequencies in Malignancy Prediction in Thyroid Nodules.

[OBJECTIVE] To investigate the frequency of micronuclei (MN) and binucleated (BN) cells in thyroid nodules and adjacent normal tissue, and evaluate their correlation with cytological (Bethesda classification) and histopathological diagnoses to assess their potential utility in preoperative malignancy prediction.

[METHODS] This prospective study included 39 patients (16 benign, 19 papillary carcinoma, 4 follicular carcinoma) who underwent thyroidectomy. Tissue samples from both nodular and adjacent normal thyroid regions were collected. MN and BN frequencies were evaluated in 1000 cells per sample using May-Grünwald and 5% Giemsa staining. Data were analyzed in relation to Bethesda categories and final surgical pathology using mixed-effects models in R 4.4.1. ROC analysis was conducted to assess the diagnostic performance of MN/BN frequency.

[RESULTS] MN and BN frequencies were significantly higher in nodular tissue compared to adjacent normal thyroid tissue (p < 0.05). Malignant lesions showed significantly increased MN/BN frequencies compared to benign ones, although no significant difference was observed between papillary and follicular subtypes (p < 0.05). MN/BN frequencies were also significantly higher in Bethesda categories III-VI compared to categories I-II (p < 0.05). No significant variation was found in normal thyroid tissue across cytological or pathological groups.

[CONCLUSION] MN and BN cell frequencies were elevated in malignant nodules and higher Bethesda categories, supporting their potential role as adjunctive cytogenetic markers in thyroid nodule assessment. While findings are promising, their diagnostic utility in indeterminate nodules remains unclear. Larger, FNAB-based studies are required to validate their feasibility and clinical relevance in routine preoperative evaluation.