Smoldering multiple myeloma

Radiopaedia • CC-by-nc-sa 3.0 • de

Smoldering multiple myeloma is a premalignant stage between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma.

Clinical presentation

Similar to MGUS patients, smoldering multiple myeloma patients are asymptomatic.

Diagnostic criteria

The criteria for smoldering multiple myeloma diagnosis according to the International Myeloma Working Group include :

  • serum M-protein ≥3 g/dL or urinary monoclonal protein ≥500 mg per 24 hours and/or clonal plasma cell population present in the bone marrow (10-60% cellularity)
  • as well as the absence of a 'myeloma-defining event' (e.g. hypercalcemia, renal insufficiency, lytic bone lesions, anemia) or amyloidosis

Radiographic features

MRI

MRI is of prognostic importance in smoldering multiple myeloma . 50% of patients with smoldering multiple myeloma have abnormal bone marrow on MRI ranging from focal to diffuse changes . Patients with marrow changes on MRI have a much shorter time to progression than those without .

Treatment and prognosis

On average 10% of smoldering multiple myeloma patients per year will develop active multiple myeloma .