Imaging findings of extraosseous multiple myeloma
© International Cancer Imaging Society 2002
Accepted: 20 May 2002
Published: 5 May 2015
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.
KeywordsCT US mammography myeloma
Patients and methods
We retrospectively reviewed the radiological files of 200 myeloma patients in two Jerusalem hospitals and recorded all the cases that had extraosseous masses. The organs involved and the imaging findings were recorded. Patients with extraosseous myeloma in contiguity with bony involvement were excluded from our series.
Out of the 200 patients we found eight cases of extraosseous myeloma (age range 48–82 years, mean age 60 years). Two patients were men, and six were women. CT was available in six patients, mammography in three patients, and ultrasound in one patient. Different sites of extraosseous involvement were present: breast (three patients), lymph nodes (one patient), thyroid cartilage (one patient), pancreas and stomach (one patient), adrenal and pleura (one patient), meninges (one patient). Two patients had masses in more than 1 site (adrenal and pleura; stomach and pancreas). Definite histologic diagnosis of plasmacytoma was available in all cases.
Extraosseous myeloma is an uncommon and more aggressive form of multiple myeloma. It is found in less than 5% of myeloma patients. Submucosal tissue of the upper airways was reported as the most frequent site of involvement. Extramedullary plasmacytomas have also been encountered in the gastrointestinal tract, lymph nodes, spleen, parotid gland, vagina, breast, pancreas, thyroid and testes.
Sonography was performed in one case and showed a solid well-demarcated mass with homogeneous echo texture resembling a benign lesion (Fig. 1(b)).
Stomach and pancreas
Involvement of the lungs and pleura in multiple myeloma is also rare. Our case demonstrates multiple pleural masses indistinguishable from mesothelioma (Fig. 4(b)). There was no evidence of rib involvement. We also found one case of plasmacytoma involving the thyroid cartilage.
Central nervous system (CNS)
CNS involvement independent of bone lesions occurs in less than 1% of patients with multiple myeloma. One of the patients in our series had an extra-axial mass arising from the meninges with CT imaging findings similar to those observed in patients with meningioma.
In conclusion, our small series presents a gamut of extraosseous findings in various organs. Extraosseous myeloma is very rare and may involve various organs and systems. Clinicians and radiologists should be aware of these rare manifestations and consider this possibility whenever a myeloma patient develops an extraosseous mass.
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