Validating micronucleus score in effusion fluids

Background: Identifying malignant cells in effusion fluid is vital in staging and management of cancers. Differentiating reactive mesothelial cells from malignant cells in effusion fluid is a challenging task and there is an ongoing need for simpler and cost effective tool to aid the diagnosis. Micronucleus is an additional smaller nucleus in the cytoplasm, formed by chromosomes or chromosomal fragments formed during cell division. Aims: The aim of this study was to assess the significance of micronucleated cell in effusion fluids to distinguish adenocarcinomatous from reactive mesothelial effusions. Materials and Methods: Thirty cases of unequivocal malignant effusion fluids and 30 benign cases with reactive mesothelial cells as control were studied. Number of microucleated cells present per1000 well-preserved cells in Leishman-stained smears were counted. Results: Mean (±SD) micronucleated score in malignant and benign effusions were 15.77 ± 9.78 and 1.87 ± 1.78, respectively. The median scores were 13 and 2, respectively. Mann–Whitney test showed that this difference was statistically significant (P < 0.001). This study revealed that there was a significant difference in micronucleus scoring between benign and malignant effusions. Conclusions: Micronucleus score can be used as an additional biomarker in the interpretation of routinely stained cytosmears.