Diagnostic Utility of the Immunohistochemical Markers Calretinin (CAL) and Epithelial Membrane Antigen (EMA) in Differential Diagnosis of Reactive Mesothelial Cells (RMC), Malignant Mesothelioma and Metastatic Adenocarcinoma (AC) in Serous Effusions

Objective-In present study, an attempt was made to compare conventional smear and cell block technique and to differentiate equivocal cytomorphological cases, reactive mesothelial cells and neoplastic cells on the basis of Calretinin and Epethilial Membrane Antigen immunohistochemistry. Methodology- In the present study 50 body cavity fluid specimens were evaluated by simultaneous use of smear and cellblock technique in Pathology department. First diagnosis was made on histopathological basis and then paraffin embedded sections were subjected to immunohistochemistry for Calretinin and Epethilial Membrane Antigen. Results The additional yield for malignancy was 18 % in cell block as compared to conventional smear. Calretinin proved to be an efficient marker for mesothelial cells with sensitivity 100 %, specificity 94.4 %, positive predictive value 96.9 % and negative predictive value 100 % (p-valueless than0.05) and Epethelial Membrane Antigen for adenocarcinoma cells with sensitivity, specificity, positive predictive value and negative predictive value of 100 %, 93.75 %, 90 %, 100 % respectively (p-valueless than0.05) Conclusions Cellularity, morphological details and architectural patterns are better appreciated in conventional smear than cell block, with an additional diagnostic yield of malignancy. If supplemented with immunohistochemistry proved to be an useful adjuvant in evaluating serous effusions for a accurate diagnosis.