The overall incidence is thought to be ~10% (range 5-16%) of those diagnosed with myeloma 3,7,8. It is considered to be more common in younger patients and in those with non-secretory myeloma and IgD myeloma3.
Diagnosis
In most cases, especially patients with a coexisting malignancy, tissue diagnosis is often considered essential.
Pathology
This can potentially affect any organ system and the reported disease spectrum includes:
Imaging features are non-specific and widely variable depending on the site. The condition can mimic other pathologies. When there is known background multiple myeloma, the development of focal soft tissue masses should be considered highly suspicious for extraosseous myeloma. In particular, the development of extraosseous soft tissue masses in a myeloma patient after stem cell transplantation should raise suspicion for extraosseous myeloma. It is important to know if there is more than one lesion.
Treatment and prognosis
The presence of extraosseous myeloma generally implies a poorer prognosis 3. More content required for treatment.
Differential diagnosis
Extraosseous myeloma can mimic a vast number of entities dependent on location. If there is only one lesion and the lesion reveals myelomatous / plasma cells on a biopsy, consider extramedullary plasmacytoma.
3. Hall MN, Jagannathan JP, Ramaiya NH et-al. Imaging of extraosseous myeloma: CT, PET/CT, and MRI features. AJR Am J Roentgenol. 2010;195 (5): 1057-65. doi:10.2214/AJR.10.4384 - Pubmed citation
4. Vigo F, Ciammella P, Valli R et-al. Extraskeletal multiple myeloma presenting with an atrial mass: a case report and a review of the literature. J Med Case Rep. 2012;6 (1): 236. doi:10.1186/1752-1947-6-236 - Free text at pubmed - Pubmed citation
5. Boyadjis TA, D'Altorio RA. Orbital involvement by multiple myeloma: case report. J Comput Tomogr. 1986;10 (2): 145-6. Pubmed citation
6. Ajithkumar TV, Sivasankar C, Ramachandran K. Orbital multiple myeloma: case report and review of computed tomography features. Australas Radiol. 2002;46 (1): 119-20. Pubmed citation
7. Patlas M, Khalili K, Dill-Macky MJ et-al. Spectrum of imaging findings in abdominal extraosseous myeloma. AJR Am J Roentgenol. 2004;183 (4): 929-32. doi:10.2214/ajr.183.4.1830929 - Pubmed citation