DNA Flow cytometry and immunohistochemical evaluation of effusion specimens

Introduction: Effusion is an abnormal fluid accumulation in any of the body cavities, reflects some pathology and requires rapid diagnosis. Adenocarcinomas afflicting the lung, ovary and breast frequently metastasize to the serosal cavities. Many patients affected by neoplasm come with complaints of accumulation of fluid in one of the serosal cavities. The analysis of DNA ploidy through flow cytometry (FCM) has been used to increase the accuracy and speed of analysis of effusions. Hence, the aim of this study was to assess and compare the utility of DNA flow cytometry and epithelial membrane antigen immunohistochemistry (EMA-IHC) for detection of carcinoma cells in effusion fluids with conventional cytology as bench mark. Materials and Methods: 31 patients with serous effusions (28 pleural, 4 peritoneal) of various aetiologies were included in this prospective study. All the cases were analysed by DNA flow cytometry as well as by conventional cytological examination using modified Leishman stain and Papanicolaou stain, followed by EMA immunohistochemistry (IHC) on the cell blocks. Results: Out of the 31 samples studied 26 were benign and 5 were malignant. Cytology and DNA FCM analysis showed sensitivity and specificity of 75% and 96.3% respectively while EMA-IHC showed sensitivity of 75% and specificity of 92.6%. Conclusion: DNA flow cytometry is more valuable than EMA-IHC and a useful supplementary diagnostic modality to conventional cytology for detection of malignancy in effusion specimens.