{Reference Type}: Case Reports {Title}: Intravascular large B-cell lymphoma as a covert trigger for hemophagocytic lymphohistiocytosis complicated with capillary leak syndrome: a case report and literature review. {Author}: Wen J;Xu J;Ji J;Zhang W;Zheng Q;Liu T;Zheng Y;Ma H; {Journal}: Front Immunol {Volume}: 15 {Issue}: 0 {Year}: 2024 {Factor}: 8.786 {DOI}: 10.3389/fimmu.2024.1403376 {Abstract}: Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of non-Hodgkin lymphoma. Patients with hemophagocytic lymphohistiocytosis (HLH)-associated IVLBCL variants exhibit significantly poor survival. Cytokines play pivotal roles in malignancy-associated HLH as well as in capillary leak syndrome (CLS). The pathogenesis of CLS involves hyperpermeability and transient endothelial dysfunction. Here, we report the first case of HLH-associated IVLBCL variant complicated with CLS. The patient presented with fever, refractory hypoproteinemia, hypotension and severe edema, followed by telangiectasias. Treatment with etoposide and dexamethasone and hydroxyethyl starch-based artificial colloid led to transient improvement. The diagnosis of IVLBCL was confirmed after the sixth bone marrow biopsy. Subsequently, the R-CHOP (rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone) regimen was administered and resulted in prompt alleviation of CLS and HLH symptoms. The patient has survived for more than 6 years after combination of immunochemotherapy and autologous peripheral stem-cell transplantation. This case provides some insights into the mechanism and clinical management of IVLBCL complicated with HLH and CLS. Similar cases concerning lymphoma-associated CLSs were also reviewed.