Micronucleus Scoring in Fine Needle Aspiration Cytology of Breast LesionsA Retrospective Analytical Study

Introduction: Micronuclei and other nuclear abnormalities are biological indicators of genotoxicity and chromosomal instabilities. Breast lesions are frequently encountered in routine clinical practice and Fine Needle Aspiration Cytology (FNAC) is used as a routine diagnostic modality. Aim: To identify the utility of micronucleus scoring in classifying and diagnosing palpable breast lesions with FNAC. Materials and Methods: The present study was a two year retrospective analysis in the Department of Pathology of Guntur Medical College and Government General Hospital, Guntur, Andhra Pradesh. Case records and FNAC smears of breast lesions in the period from March 2018 to February 2020 were retrieved from the departmental archives. Data was analysed in the month of September 2020. A total of 108 cases were included in the study. Micronucleus scoring was done on the FNAC smears independently by two institutional pathologists who were blinded to clinical data and final diagnosis and mean micronuclear scores were obtained. Statistical analysis was done using Chi-square test on Statistical Package of the Social Sciences (SPSS) software (version 14) to determine the significance of micronuclear score in differentiating benign and malignant lesions, and in grading the malignant tumours. Results: All the cases were classified into four categories: benign, atypical favouring benign, suspicious of malignancy, invasive breast carcinoma on cytology. In the present study it was found that micronucleus scoring was effective in differentiating various benign and malignant breast lesions (p-value=0.0001) and also in grading of malignant tumours (p-value=0.05). The results obtained showed that there exists a significant level of correlation with other well established standard grading systems (Pearson correlation coefficient=0.94). Conclusion: The present study revealed that micronucleus scoring is indeed a useful and reliable method for diagnosing breast lesions and can be used as an adjunct in classifying difficult and borderline cases on cytology