Neoplastic angioendotheliosis: ultrastructural study and review of the literature.

Neoplastic angioendotheliosis is a rare disorder characterized by progressive multifocal neurological deficit and dementia. The principal pathological findings are multiple infarcts in the brain and spinal cord and the microscopical demonstration of proliferated neoplastic cells, primarily within the lumens of arteries, arterioles, and capillaries. Vessels of the central nervous system are the most severely affected and appear to be the primary site of neoplastic proliferation. Systemic intravascular and focal extravascular proliferation can also be identified. The endothelial origin of the neoplastic cell with a gradation of changes from normal to neoplastic is demonstrated by the electron microscopical study of involved meningeal vessels. Our patient and those reported in the literature all demonstrate involvement of the central nervous system. In addition, an elevated cerebrospinal fluid protein level is present in all patients for whom that information is available, and fever and renal involvement are frequently present. Steroid therapy is generally ineffective. If the disease is suspected clinically, our studies suggest that meningeal biopsy is the diagnostic procedure of choice to help determine whether chemotherapy should be instituted.