[Diffuse large B-cell lymphoma initially manifesting in bone marrow. A case report].

We presented the case of diffuse large B-cell lymphoma initially manifesting in bone marrow without lymph nodes' swelling and other extranodal lesion. A 68-year-old woman was suffering from general fatigue and fever. Because atypical cells were identified in the peripheral blood, a bone marrow puncture and random skin biopsy were performed. In myelogram, it was suspicious for myelodysplastic disease because lymphoma cells resembled other atypical hematopoietic cell. In biopsy specimen of bone marrow, atypical cells diffusely infiltrated, which could be called "paced bone marrow". On the other hand no atypical cell identified in the vessels of dermis and subcutaneous tissue by random skin biopsy. Immunohistochemically, atypical cells in bone marrow were diffusely positive for B-cell marker (CD20). These results lead this case to be diagnosed as diffuse large B-cell lymphoma initially manifesting in the bone marrow. In this case, it was very useful that bone marrow biopsy and myelogram were evaluated simultaneously. Quick and accurate diagnosis is possible by combining immunohistochemical analysis using both myelogram and biopsy specimen.