Cellular characteristics of neoplastic angioendotheliosis. An immunohistological marker study of 6 cases.

Neoplastic angioendotheliosis (NAE) is a rare, mostly fatal disease characterized by proliferation of large blastoid cells in small vessels of various organs. The origin of neoplastic cells remain undetermined. In this study, cell markers were studied immunohistologically on paraffin sections of six cases of NAE, by applying avidin-biotin-peroxidase (ABC) method and five antibodies which can demonstrate marker antigens on formalin fixed and paraffin embedded specimens. It was shown that the neoplastic cells were heavily stained with an anti-B lymphocyte monoclonal antibody LN-1 (6/6), moderately stained with another anti-B lymphocyte antibody LN-2 (5/6) and heavily stained with a monoclonal antibody which reacts with all levels of leukocytes (Dako-LC) (6/6). The cells did not show positive reaction with an anti-myelomonocytic antibody anti-Leu M1. The reaction against anti-Factor VIII, which can depict endothelial cells, was mostly negative, and if positive, was faint and indefinite, leading to an assumption that the reaction was against antigens in serum and not against neoplastic cells. These results suggest that the neoplastic cells of NAE are in the B lymphocyte lineage.