Intravascular lymphoma is an extremely rare, disseminated, and aggressive extranodal CD20+ non-Hodgkin's lymphoma characterized by the presence of lymphoma cells only in the lumina of small vessels. We report a 72-year-old woman with a diagnosis of intravascular lymphoma presented with splenomegaly and leukemic appearance in the peripheral blood smear. Her clinical course was rapidly deteriorated before the initiation of specific chemotherapy and finally died due to multiorgan insufficiency. Bone marrow biopsy revealed a characteristic infiltration of CD5, CD10 B-cell lymphoma. To our knowledge, this is the first reported case of a CD5, CD10 intravascular B-cell lymphoma with leukemic presentation in peripheral blood with multiple cytogenetic aberrations.