This case of a young patient with multiple myeloma with extramedullary disease (EMD), published in Oncology (Williston Park), illustrates important points regarding the role of imaging and therapy selection in optimizing diagnosis and treatment of this disease.

Multiple myeloma involves the proliferation of malignant B cells in bone marrow and production of an abnormal antibody called M protein; the disease is associated with progressive skeletal destruction and end-organ damage. Although most patients with multiple myeloma have disease restricted to the medulla (the cavity of the bone housing bone marrow), some patients develop disease that is outside the bone medulla, such as in the soft tissues or organs — extramedullary disease — as a result of hematogenous disease spread.

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Although the prevalence of EMD is unclear, estimates indicate less than 10% of patients have extramedullary disease that is distant from the bone at diagnosis, with kidney and skin being 2 of the more common sites of extramedullary involvement. Nevertheless, prevalence has been reported to increase as the disease progresses. Importantly, extramedullary multiple myeloma, either at diagnosis or relapse, is associated with an aggressive form of the disease and worse clinical outcomes compared with multiple myeloma not characterized by extramedullary disease.

In this case, a previously healthy 39-year-old woman presented to the emergency department with progressive abdominal pain, limited mobility associated with a right gluteal mass, anemia, and involuntary weight loss. Additional blood tests revealed hyperglobulinemia, hypercalcemia, elevated serum creatinine level, and prolonged prothrombin time, among other abnormalities. Computed tomography showed evidence of ascites, splenomegaly, and hepatomegaly with multiple hypervascular liver lesions, as well as a number of skeletal lytic lesions. A diagnosis of multiple myeloma was confirmed following serum quantitative immunoglobulin, serum free light chains, and serum protein electrophoresis testing, as well as an assessment of cytogenetic abnormalities in a bone marrow biopsy specimen.

Unfortunately, the patient died within a few days of presentation following rapid clinical deterioration. A scientific medical autopsy revealed the patient had disease consistent with extramedullary multiple myeloma that affected the gluteus muscle, ovaries, kidneys, and peritoneum.

“Considering the adverse impact that extramedullary disease has on clinical outcomes, the molecular and cytogenetic heterogeneity of multiple myeloma, and the lack of extramedullary disease-specific predictive scores, it is imperative that diagnostic strategies for this disease presentation be optimized,” the authors stated.