Primary bone marrow diffuse large B cell lymphoma: a case series and review

Diffuse large cell lymphoma involving bone marrow is not uncommon, but primary, de novo, bone marrow diffuse large B cell lymphoma (DLBCL) is rare. To understand the clinical features and outcomes of this distinct entity, we collected 12 cases in 5 years from a single-center database. They accounted for 1.16% of lymphoma, or 2.65% of diffuse large B cell lymphoma. Nine cases presented with fever of unknown origin. Lactate dehydrogenase levels were elevated in all but one case. Nine cases belonged to the high-risk group according to their international prognosis indexes (score 4 or 5). Four patients received no chemotherapy, all of whom died within 1 month. Four patients received cyclophosphamide, adriamycin, vincristine, and prednisolone (CHOP)-like chemotherapy, and their median survival was 13 months. Finally, four patients received rituximab 375 mg/m² in addition to CHOP-like chemotherapy. All of them had complete remission and three are still alive without relapse. We concluded that primary bone marrow DLBCL is a rare but distinctive subtype of lymphoma. The prognosis for this entity is poor but rituximab-based treatment is promising for improving its outcomes.