# Extramedullary Disease—Achilles Heel in Myeloma?

## TL;DR

Extramedullary disease in multiple myeloma is a severe form with poor outcomes due to complex biological mechanisms.

## Contribution

The paper highlights the unique pathogenesis and poor prognosis of true extramedullary disease in myeloma.

## Key findings

- Extramedullary disease is aggressive and associated with poor patient outcomes.
- True EMD involves plasmacytomas independent of bone and has a particularly poor prognosis.
- Advanced imaging and immunotherapy have improved detection and treatment, but more studies are needed.

## Abstract

Despite advances in therapy, extramedullary disease (EMD) remains an aggressive form of multiple myeloma associated with poor outcomes. Patients with true EMD, in which plasmacytomas have become completely independent of bone, have a particularly poor prognosis. The pathogenesis of EMD is driven by complex mechanisms involving loss of adhesion molecules, heterogeneous genetic and epigenetic changes, and a solid tumor‐like architecture within the microenvironment. Although the introduction of advanced imaging techniques and immunotherapy has led to improved detection and more promising outcomes and regimens, respectively, more prospective studies dedicated to true EMD are needed.