Immunohistochemistry

Immunohistochemistry is important for both distinguishing benign mesothelial proliferations from diffuse malignant mesothelioma (DMM) and for differentiating DMM from metastatic malignancies involving the pleura. Histologic diagnosis alone is often impossible. The exact makeup of immunohistochemical panels used for DMM diagnosis depends on the differential diagnosis and on the antibodies available in a given laboratory. Distinguishing reactive mesothelial cell hyperplasia from DMM is a significant challenge for which the role of immunohistochemistry is limited; however, it is extremely helpful when examining tissue for invasion to the stroma, fat, or lung parenchyma. The role of immunohistochemistry is also relatively limited in sarcomatous DMM diagnosis because mesothelial markers are less often positive.