Primary Diffuse Large B Cell Lymphoma of Bone: A Single-Center Experience

Background: Primary diffuse large B-cell lymphoma of the bone (PB-DLBCL) is a rare type of extra-nodal lymphoma. This study aimed to examine the clinical characteristics, outcomes, treatment modalities and risk of central nervous system relapse (CNSR) among adult Jordanian patients with PB-DLBCL. Methods: This retrospective study included patients aged >16 years who were diagnosed with PB-DLBCL and treated at our hospital between 2002 and 2021. Clinical characteristics, treatment modalities, outcomes and CNSR events were extracted from the hospital's data system and analysed. Patients were categorised into unifocal (UF) and multifocal (MF) PB-DLBCL groups according to the number of bone sites involved. The involvement of only one site was defined as UF, whereas the involvement of two or more sites was defined as MF. Results: In total, 12 patients were diagnosed with PB-DLBCL. Their median age was 47.5 years (range, 17-80 years). The male: female ratio was 1:1. There were eight patients in the UF PB-DLBCL group and four in the MF PB-DLBCL group. All patients received treatment with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone. In the UF PB-DLBCL group, the male:female ratio was 5:3, the median age was 41 years, and the follow-up duration was 9-135 (mean, 83.3) months. In the MF PB-DLBCL group, the male:female ratio was 1:3, the median age was 51.5 years, and the survival time was 3-11 (mean, 7) months. Three patients with vertebral UF PB-DLBCL underwent early vertebroplasty without complications. The most common site involved was the vertebral column. Most patients with UF PB-DLBCL achieved complete remission (CR), whereas no patients with MF PB-DLBCL achieved CR. Conclusion: PB-DLBCL is rare in adult Jordanian patients. UF PB-DLBCL is more common than MF PB-DLBCL. Patients with UF PB-DLBCL had a good prognosis. Patients with MF PB-DLBCL had a high international prognostic index score, risk of CNSR and short survival time.