IMMUNOHISTOCHEMICAL EXPRESSION OF ENDOTHELIAL MARKERS IN LEFT ATRIAL MYXOMAS - A STUDY OF 6 CASES

Vascular endothelial cells are antigenically heterogeneous and therefo re it has been recommended that a range of immunohistochemical markers is employed to show the presence of cells of endothelial origin in su rgical pathology. In this study we applied three monoclonal antibodies -to factor VIII-related antigen, JC70 (CD31), QBend 10 (CD34)-and Ulex europaeus agglutinin type 1 lectin (UEA-1), to six consecutive cases of left atrial myxoma. We found that JC70 and QBend 10 consistently st ained myxoma cells in all their different growth patterns contrasting with factor Vm-related antigen expression and UEA-1 binding which were restricted to areas which showed morphological evidence of vascular d ifferentiation. These findings suggest that the constituent cells of a trial myxomas show more widespread endothelial differentiation than ha s previously been recognized and that differences in immunohistochemic al staining may reflect the maturation status of these cells.