Morphological markers of chromosomal instability as predictors of malignancy in pleural effusion

Abstract

BackgroundMalignancy in pleural effusion is an indication of poor prognosis. The distinction between malignant cells and reactive mesothelial cells in effusion cytology is sometimes difficult and requires ancillary techniques. Evaluation of morphological indicators of chromosomal instability (CI) like micronuclei (MN), chromatin bridging (CB), nuclear budding (NB), and multipolar mitosis (MM) on routine cytology smears is a promising tool to distinguish malignant from benign ascitic fluids. However, it has been scarcely evaluated in pleural effusions. The present study was conducted to evaluate the diagnostic value of these markers in differentiating between malignant and benign pleural fluids.MethodsIt is a cross sectional study in which a total of 72 pleural fluid samples over a period of 2 years received in the cytology department of the hospital were evaluated. The cytological analysis was done by two independent cytopathologists and interpreted as either malignant or benign. Four morphological markers of CI were counted in the May‐Grünwald Giemsa (MGG) stained smears of all the cases and the score was compared with the conventional cyto‐morphological diagnosis.ResultsOut of 72 cases, there were 42 malignant and 30 benign effusions on cytological examination. The mean score of micronuclei count, nuclear budding, chromatin bridging and multipolar mitosis in malignant effusions were 7.26 ± 2.74, 9.55 ± 5.53, 1.83 ± 1.17, and 2.21 ± 1.62 respectively that was significantly higher than the benign effusions (1 ± 0.71, 1.1 ± 0.86, 0.38 ± 0.50, and 0.15 ± 0.37 respectively) (p < .05). On Receiver operating characteristic (ROC) curve analysis, a cut‐off of 5 for the MN count had a sensitivity of 88% and specificity of 100% in detecting malignant pleural effusion [Area under curve (AUC) 95.8%, p < .001].ConclusionEvaluation of morphological indicators of CI on routine MGG stained smears is a simple and cost‐effective method to differentiate between benign and malignant pleural fluids.