Extramedullary disease in multiple myeloma

Abstract

When clonal plasma cells grow at anatomic sites distant from the bone marrow or grows contiguous from osseous lesions that break through the cortical bone, it is referred to as extramedullary multiple myeloma (EMD). EMD remains challenging from a therapeutic and biological perspective. The pathogenetic mechanisms are not completely understood and it is generally associated with high-risk cytogenetics which portends poor outcomes. There is a rising incidence of EMD in the era of novel agents, likely a reflection of longer OS, with no standard treatment approach. Patients benefit from aggressive chemotherapy-based approaches, but the OS and prognosis remains poor. RT has been used for palliative care. There is a need for large prospective trials for development of treatment approaches for treatment of EMD.

Fig. 1. Pathogenesis of extramedullary spread in multiple myeloma.

SDF-1- Stromal cell derived factor-1, CXCR-4- Chemokine receptor type 4, VLA-4- Very late antigen-4, VCAM-1- Vascular cell adhesion protein-1, VEGF- Vascular endothelial growth factor, TNF-a- Tumor necrosis factor- alpha, HGF- Hepatocyte growth factor, IL-6- Interleukin-6.