Objective: To evaluate the expression of these markers individually and to find out which markers would be the most effective in a diagnostic panel to reliably discriminate these lesions.
Study design: Sections from cell blocks of these fluids were stained with antibodies against calretinin, EMA, HMFG-2, BerEp4, B72.3 and CEA. A preliminary diagnosis was formulated based on cytomorphologic criteria. Subsequently, results of all 6 immunocytochemical stainings were evaluated, the most effective diagnostic pane of antibodies was proposed and staining results using this panel were compared to results obtained by solely cytomorphologic evaluation and to the ultimate diagnosis.
Results: Additional immunocytochemical staining with the proposed panel of calretinin, EMA, HMFG-2 and CEA improved sensitivity for malignancy in general from 78% to 96% and specificity from 73% to 91%. Sensitivity for malignant mesothelioma increased from 45% to 91%, with an increase in specificity from 87% to 96%. Sensitivity for adenocarcinoma decreased slightly from 100% to 92%, but specificity increased from 86% to 100%. Overall, diagnostic accuracy increased from 76% to 94%.
Conclusion: Immunocytochemical staining of standardized cell block reparations of serous fluid cells with a small panel of 4 antibodies significantly improves diagnostic results compared to cytomorphologic evaluation alone.