Intravascular T-cell lymphoma: A rare, poorly characterized entity with cytotoxic phenotype.

Intravascular T-cell lymphomas are rare, poorly characterized lesions. We discuss the clinical, radiologic and especially the laboratory characteristics of a lesion which presented in a 62-year-old woman with a history of progressive CNS abnormalities. Throughout the course of the disease, radiologic findings consisted mainly of multifocal mixed areas of ischemia and vasogenic edema involving cortical and subcortical regions. A brain biopsy identified an abnormal T-cell population confined to lumens of vessels. These T-cells were abnormal cytotoxic cells, positive for CD3, CD8, and negative for CD2, CD4, CD5, CD7 and CD30. While flow cytometry and immunohistochemistry failed to identify a similar population in the blood or bone marrow, molecular studies showed a clonal T-cell population in both the brain and the bone marrow. No other organs were involved. In spite of aggressive treatment, the patient's medical condition continued to progress and she passed away. In conclusion, this abnormal population of cytotoxic T-cells with intravascular localization probably represents a specific type of T-cell lymphoma with specific clinical, radiologic, molecular and immunophenotypic characteristics.