The Asian variant of intravascular lymphoma (AIVL) is characterized by hemophagocytic syndrome, pancytopenia and hepatosplenomegaly but usually lacks any neurological abnormality and skin lesions, which are typical features of classical intravascular lymphoma (IVL). An ante-mortem diagnosis of AIVL is difficult due to the absence of visible lymphoma lesions and unspecific clinical manifestations. A definite diagnosis relies on the presence of neoplastic B cells in the lumina of small vessels. Paraffin block samples of aspirated bone marrow clots were obtained from 4 patients with clinically suspected IVL and subjected to immunohistopathological analysis. All samples exhibited CD 20+ or CD 79a+ lymphoma cells proliferating intravascularly as well as erythrocytic hemophagocytosis. The distribution of neoplastic cells in the structure of the bone marrow allowed IVL to be distinguished from bone marrow invasions due to other types of lymphoma. We demonstrated the successful establishment of a definite ante-mortem diagnosis of AIVL in 3 of 4 patients by the rapid and simple method of using aspirated bone marrow samples.