Intravascular B-cell lymphoma following nodal diffuse large B-cell lymphoma.

Intravascular lymphoma was first described in the literature as angioendotheliomatosis proliferans systemisata approximately 50 years ago.1 At that time, it referred to malignant cells that were almost completely restricted to intraluminal spaces and were thought to arise from endothelial cells. In the mid-1980s, some studies suggested an association between malignant angioendotheliomatosis and lymphoma and raised the possibility that these conditions might be a single disease with hematopoietic origins.2,3 Advances in immunophenotyping ultimately revealed that these neoplastic cells were actually lymphocytes.4 Intravascular lymphomas are a rare subtype of large cell lymphoma characterized by the proliferation of malignant lymphocytes within the lumina of small blood vessels with little to no extravascular involvement.1 The malignant cells usually have a B-cell phenotype, although some cases of intravascular T-cell lymphoma have been reported. Since intravascular lymphoma is rare—with most cases discovered postmortem—most of the information about this condition comes from case reports and small case series.