Desmin is mainly an intermediate filament of a protein of the smooth as well as striated muscles. IHC-Desmin, or in other words immunohistochemistry desmin, is a particular test that is used to distinguish between mesothelial cells and carcinoma in serous fluid during the cell block preparations. The sole purpose of the test is to get a better insight of the immunohistochemical stains for desmin while discriminating mesothelial cells from adenocarcinoma in the serous fluid at the time of cell block preparations. The test is highly beneficial for the purpose of detecting tumors of myogenic origin.