Histogenesis of post-mastectomy angiosarcoma--an ultrastructural study.

An example of post-mastectomy angiosarcoma was studied by electron microscopy to determine its histogenesis. Unequivocal evidence of endothelial differentiation was found in well and poorly differentiated areas. Positive staining for factor VIII related antigen and negative staining for epithelial membrane antigen further confirmed that the tumour was a true angiosarcoma rather than a peculiar form of carcinomatous metastasis.