Diffuse large B-cell lymphoma, not otherwise specified presenting with bone and bone marrow involvement in the absence of lymphadenopathy.

A 74-year-old woman visited our hospital because of right chest pain and fatigue. Laboratory examinations revealed pancytopenia and an elevated level of serum lactate dehydrogenase. Although bone lesions were detected by computed tomography, there was no lymphadenopathy. Blastoid cells were evident in the bone marrow. From the patient's medical history and results of immunohistological and chromosomal analysis, she was diagnosed as having diffuse large B-cell lymphoma, not otherwise specified. This form of presentation of diffuse large B-cell lymphoma is very rare, and emphasizes the need for careful evaluation of such cases, including bone marrow biopsy for accurate diagnosis.