Intravascular large B cell lymphoma (IVBCL) is a rare type of extranodal large B cell lymphoma characterized by selective growth of lymphoma cells within the microvasculature. Patients can present with a confusing complex that reflects organ dysfunction secondary to vascular obstruction or systemic symptoms such as unexplained fever. Two major patterns of clinical presentation have been recognized: a Western form characterized by symptoms related to involvement of the central nervous system and skin, and an Asian variant in which the patients present with multiorgan failure, hepatosplenomegaly, pancytopenia and hemophagocytic syndrome. However, the lymphoma is usually widely disseminated in extranodal sites including bone marrow, spleen, liver, lungs, skin, nervous system, but rarely in blood.

The diagnosis of IVBCL is made by demonstrating the presence of large lymphoma cells within small to medium sized blood vessels. The neoplastic cells are typically positive for CD20, CD79a, and negative for CD3 and CD34.

The R-CHOP (Rituximab, Cyclophosphamide, Hydroxyaunomycin, Oncovin, Prednisone) drug combination plus CNS prophylaxis is the treatment of choice in patients without nervous system involvement. CNS involvement and recurrence is still challenging to manage despite the improvement in clinical outcomes induced by Rituximab plus chemotherapy.

This slide shows CD20 stain. See related content for H&E stain.