Waldenström macroglobulinemia: a challenging case treated with anti-CD19 CAR-T cell therapy.

Waldenström macroglobulinemia (WM) is characterized by lymphoplasmacytic lymphoma associated with large amounts of monoclonal immunoglobulin M (IgM) protein (Owen et al., 2003). Common signs and symptoms include fatigue due to anemia, lymph node enlargement, hepatosplenomegaly, thrombocytopenia, symptoms related to high viscosity, and peripheral neuropathy, among others. Despite significant advances in WM treatment, this type of indolent lymphoma remains incurable, with a wide array of patient outcomes (Ruan et al., 2020). In recent years, chimeric antigen receptor T (CAR-T) cell therapy targeting cluster of differentiation 19 (CD19) has shown unprecedented response rates and durability in the treatment of B-cell malignancies. In this report, we describe a challenging case of WM that involved multiple extramedullary sites, relapsed, and was refractory to chemotherapy, immunotherapy, and targeted therapy. After anti-CD19 CAR-T cell therapy, the tumor burden significantly decreased and the patient's condition remained stable at the writing of this report.