Clinical characteristics and prognostic factors of plasmablastic lymphoma patients: analysis of 135 patients from the LYSA group

Background: Plasmablastic lymphoma (PBL), initially described in 1997 in the oral cavity of HIV positive patients, is now recognized as a distinct aggressive and rare entity of diffuse large B-cells lymphoma by the World Health Organization (WHO) classification. Since the original description, others cases have been reported. However, these are largely derived from case reports or small series limiting any definitive conclusions on clinical characteristics and outcome. Patients and methods: The clinical, biological, pathological features and outcome of a cohort including 135 patients with PBL, from LYSA centers in France and Belgium, were reported and analyzed. Results: The median age was 58 years, with a male predominance. The cohort was divided into 56 HIV-positive patients, 17 post-transplant patients and 62 HIV-negative/non-transplanted patients. Within HIV-negative/non-transplanted, a relative immunosuppression was found in most cases (systemic inflammatory disease, history of cancer, increased age associated with weakened immune system). We have also described a new subtype, PBL arising in a chronic localized inflammatory site, without any sign of immunosuppression. At presentation, 19% of patients showed oral involvement. Immunophenotype showed CD138 positivity in 88% of cases and CD20 negativity in 90% of cases. Chemotherapy was administered to 80% of patients, with a complete response (CR) rate of 55%. The median overall survival (OS) was 32 months. In univariate analysis, HIV positive status showed better OS when compared with HIV negative status. In multivariate analysis, International Prognostic Index score, chemotherapy and CR were associated with survival benefit. Conclusion(s): This cohort, the largest reported to date, increases the spectrum of knowledge on PBL, rarely described. However, specific guidelines to clarify treatment are lacking, and may improve the poor prognosis of this rare disease.