Clinical presentation, outcome, and prognostic markers in patients with intravascular large B‐cell lymphoma, a lymphoma study association (LYSA) retrospective study

Background Intravascular large B‐cell lymphoma (lVLBCL) is a very rare type of large B‐cell lymphoma. Methods We conducted a retrospective study on IVLBCL patients treated from 2000 to 2016 in LYSA cooperative group centers. Results Sixty‐five patients were identified in 23 centers. Median age at diagnosis was 69 years (range 23–92). Thirty‐four patients (64%) had an IPI score >3 and 40 patients (67%) had a performance status ≥2. The most frequent extra‐nodal locations were bone marrow (n = 34; 52%), central nervous system (n = 25; 39%), and skin (n = 21; 33%). Nodal involvement and endocrine system were observed in 34% (n = 22) and 18% (n = 12) of all cases, respectively. Twenty‐six patients (41%) had macrophage activation syndrome. Tumor cells were frequently CD5 positive (52%) with a non‐germinal center origin (86%). BCL2 was expressed in 87% of all samples analyzed (n = 20) and 43% of patients had a MYC/BCL2 double expression. Fifty‐six patients were treated with a regimen of chemotherapy containing rituximab, among whom 73% reached complete remission. The median progression‐free survival (PFS) and median overall survival (OS) were 29.4 months and 63.8 months, respectively. History of autoimmune disorder (Hazard ratio [HR] 3.3 [1.4–7.8]; p