Immunohistochemistry of so called "neoplastic angioendotheliosis".

Three cases of "neoplastic angioendotheliosis" were examined immunohistochemically by the peroxidase-antiperoxidase method for Factor VIII-related antigen and various leukocyte markers. In all three cases, the tumor cells stained positively for common leukocyte antigen. IgM, and kappa or lambda light chains were demonstrable in two cases. Stains for carcino-embryonic antigen and muramidase were negative. This indicates that the neoplastic cells in the lumen of blood vessels were of lymphoid origin.