Differentiating reactive mesothelial cells from metastatic adenocarcinoma in serous effusions: the utility of immunocytochemical panel in the differential diagnosis.

Differentiating reactive mesothelial cells (RMs) from metastatic adenocarcinoma cells (MAC) in serous fluids based on cytomorphologic features alone can be very challenging. Various immunocytochemical (ICC) markers have been used to maximize the diagnostic accuracy, however, cytopathologists still encounter difficulties in effusion cytologic diagnosis. The aim of this study was to evaluate previous and recent ICC stains to identify the most sensitive and specific markers and the best panel for differentiating RM from MAC.