Diagnosis and Management of Multiple Myeloma With Central Nervous System Involvement

Extramedullary presentations of multiple myeloma (MM) involving the central nervous system (CNS) carry a dismal prognosis. Although historically rare, management of extramedullary disease-including CNS manifestations-has become increasingly clinically relevant as advances in systemic therapies have prolonged control of medullary disease. CNS manifestations may occur across a variety of clinical settings and at different time points throughout the disease course. Common symptoms include visual changes, headaches, loss of sensation, confusion, and seizures. MRI identifies leptomeningeal enhancement and/or parenchymal lesions in approximately 90% of cases, and lumbar puncture with cerebrospinal fluid testing for clonal plasma cell populations is confirmatory. Encouragingly, the incorporation of novel therapeutic agents has improved historically poor outcomes in CNS MM. Novel immunotherapeutic approaches using CAR T-cell therapy and bispecific T-cell-engaging antibodies have recently demonstrated significant efficacy in consolidating responses. Multimodality treatment strategies incorporating intrathecal chemotherapy, systemic novel agents, radiation therapy, and immunotherapy hold promise for achieving more durable responses in this devastating manifestation of MM.