Imaging findings of extraosseous multiple myeloma

Multiple myeloma is characterised by a progressive proliferation of malignant plasma cells usually initiating in the bone marrow. The most common manifestations of this disease are bone involvement, renal disease and hematologic disorders. The radiological findings of diffuse osteopenia or osteolytic bone lesions are well recognised. Extraosseous myelomatous masses are found in less than 5% of multiple myeloma patients. The purpose of this essay is to acquaint the radiologist with this phenomenon and to illustrate the imaging features of the extraosseous masses of this unusual manifestation of multiple myeloma.