Intravascular large B-cell lymphoma is rare and generally fatal. It is defined pathologically by neoplastic proliferation of lymphoid cells within the lumens of capillaries, small veins, and arteries with little or no other parenchymal involvement. The diagnosis can be delayed because of the rarity of the disease and the difficulty of detection in imaging studies, and a suspicious clinical observation is warranted to make the correct diagnosis. Early diagnosis is important because delayed treatment could result in a fatal outcome. We have encountered a case of intravascular large B-cell lymphoma involving only the bone marrow. An early diagnosis was made and the patient was treated with combination chemotherapy and rituximab targeting CD20. The patient went into complete remission after the third cycle of chemotherapy and maintained a disease free state up to 6 months.

Keywords: Intravascular large B-cell lymphoma, Bone marrow, Rituximab