Immunocytochemical evidence of lymphocytic derivation of neoplastic cells in malignant angioendotheliomatosis.

Neoplastic angioendotheliomatosis is a rare disorder usually characterized by primarily cutaneous or neurological symptoms. Approximately 40 cases of malignant angioendotheliomatosis with primary central nervous system (CNS) symptoms have been reported. Some investigators have postulated a hematopoietic origin for this neoplasm. Most of the literature, however, has perpetuated the idea that the often bizarre symptoms seen with this entity result from neoplastic endothelial cell proliferation within the small vessels of affected organs, including the brain and spinal cord. This report describes the immunohistochemical examination and confirmation of the cell of origin of this neoplasm based on five previously unpublished cases of malignant angioendotheliomatosis with primarily CNS symptoms. It includes the first documentation of a T-cell lymphoma presenting as malignant angioendotheliomatosis. All cases include autopsy findings, and in four cases the diagnosis was made postmortem. One case was proven by stereotactic biopsy, but the patient succumbed as a result of severe intracranial bleeding that occurred at the time of biopsy. Tissues were studied with avidin-biotin peroxidase immunohistochemical techniques using a panel of monoclonal antibodies directed against the leukocyte common antigen, LN-1, LN-2, and anti-Factor VIII, and also using Ulex europaeus agglutinin 1. Based on the results obtained, the authors conclude that the proliferative cells seen within the vessel lumina are of lymphocytic origin and agree that the condition should more properly be designated intravascular lymphomatosis. The therapeutic implications of this conclusion point to the possible administration of chemotherapy and radiotherapy in an effort to achieve remissions in an otherwise relentlessly progressive neurological disorder.