Therapeutic options for extramedullary involvement in multiple myeloma.

Extramedullary involvement (extramedullary disease, EMD) is an aggressive subtype of multiple myeloma (MM) characterized by myeloma subclones proliferating independently of the bone marrow microenvironment, often associated with high-risk cytogenetic abnormalities, immune evasion, and treatment resistance. While significant breakthroughs have been achieved in MM treatment with the sequential approval of proteasome inhibitors, immunomodulatory drugs, and anti-CD38 monoclonal antibodies, prognosis remains poor once EMD develops. Even in the era of immunotherapy, the survival benefit for EMD patients has not shown significant improvement. This review systematically summarizes therapeutic options for MM patients with EMD, aiming to provide evidence-based guidance for EMD treatment.