Neoplastic angioendotheliosis with B lymphocyte markers on neoplastic cells: a case report.

Neoplastic angioendotheliosis (NAE) is a rare disease characterized by the occlusion of small vessels by apparently neoplastic medium-sized cells. The origin of these cells remains undetermined, mainly because the diagnosis in most of these cases has been made on autopsy. This report describes a case of NAE from whom a biopsy specimen was obtained and studied immunohistologically. The cells occluding small vessels of this patient bear B cell markers such as monoclonal immunoglobulin (mu, lambda), Leu14, B1, OKB2, and Dako-PanB, whereas they do not react with antibodies against delta- and kappa-chain of immunoglobulin (Ig), or antibodies against markers of T cells, myelomonocytic cells and endothelial cells. These results show clearly that the cells occluding the small vessels of this patient are neoplastic and of B cell lineage. This is the first case of NAE in whom the neoplastic cells in the blood vessels have been proved to be of lymphocytic lineage.