Expression of various antigens by different components of uterine mixed müllerian tumors. An immunohistochemical study.

An immunohistochemical study of keratin, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), vimentin, desmin, myoglobin and S-100 protein in 15 cases of uterine mixed Müllerian tumor was performed in order to analyze the expression of various antigens in different elements of this tumor. In general, the epithelial and mesenchymal components were separated easily by the presence of keratin/EMA or vimentin, respectively. However, in eight cases vimentin was expressed by epithelial cells and in four cases keratin by solid "sarcomatous" element. EMA was also identified in the "sarcomatous" areas of two cases. Specific differentiation was much easier to identify by immunohistochemical staining than by routine histologic examination. Areas with muscle differentiation were positive for desmin; myoglobin was identified in rhabdomyoblasts. S-100 protein was present in chondrosarcomatous and liposarcomatous areas. S-100 protein was also widely distributed in other elements. Quite diverse expression of various antigens revealed by immunohistochemistry reflects the histologic multiplicity of this tumor.