CD19-Targeted Chimeric Antigen Receptor T-cell Therapy for Concomitant Diffuse Large B-cell Lymphoma and Multiple Myeloma.

Multiple myeloma (MM) and diffuse large B-cell lymphoma (DLBCL) comprise a large fraction of hematologic malignancies diagnosed each year. However, the co-occurrence of these conditions in the same patient is rare. CD19- and B-cell maturation antigen-targeted chimeric antigen receptor (CAR) T-cell therapies have been approved in recent years with promising responses. Here, we present a patient who presented following a bone marrow biopsy that revealed MM with 20% lambda-restricted plasma cells with no evidence of lymphoma involvement in the marrow. A subsequent lymph node biopsy of a right thigh mass was done and revealed DLBCL. The patient received CD19-targeted CAR T-cell therapy and has no detectable MM or DLBCL. To our knowledge, this is the first case report in the literature describing a patient with concomitant MM and DLBCL who received CD19-targeted CAR T-cell therapy.