|Year : 2014 | Volume
| Issue : 2 | Page : 446-448
Multiple myeloma presenting as mediastinal mass
Soumya Panda1, Karthik Udupa1, Prasanth Ganesan1, Vandana Mahajan2
1 Department of Medical Oncology, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India
2 Department of Radiodiagnosis, Cancer Institute (WIA), Adyar, Chennai, Tamil Nadu, India
|Date of Web Publication||14-Jul-2014|
Department of Medical Oncology, Cancer Institute (WIA), Adyar, Chennai - 600 020, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Plasmacytomas can be classified as osseous (medullary) or non-osseous (extramedullary). Extramedullary plasmacytomas (EMP) are uncommon and may be primary or associated with multiple myeloma (MM). EMP arising from the mediastinum is extremely rare. We report two patients who presented with symptomatic mediastinal masses. On evaluation, these turned out to be EMP with coexisting MM.These two cases are being presented for their rarity and to highlight the unusual presentations of MM.
Keywords: Extramedullary plasmacytoma, mediastinum, multiple myeloma
|How to cite this article:|
Panda S, Udupa K, Ganesan P, Mahajan V. Multiple myeloma presenting as mediastinal mass. J Can Res Ther 2014;10:446-8
| > Introduction|| |
Plasmacytomas are accumulations of neoplastic plasma cells. They may arise from the bone (medullary) or from extra-osseous tissues (extramedullary plasmacytoma - EMP). EMPs constitute less than 5% of all plasma cell tumors. They may be primary or associated with multiple myeloma.  EMP arising from the mediastinum is extremely rare.  We report two cases of mediastinal plasmacytoma associated with multiple myeloma.
| > CASE REPORTs|| |
A 40-year-old male presented to our hospital with progressive breathlessness and hoarseness of voice of 2 months duration. On examination, he had tachypnea and bilateral rhonchi. Rest of the examination was unremarkable. His hemoglobin was 11 g/dl, white cell count: 8700/μl, platelet count of 397000/μl, and erythrocyte sedimentation rate (ESR) was 10 mm in 1 st hour. Biochemical parameters were normal.
Chest X-ray showed mediastinal widening with tracheal deviation to the right side with left paratracheal opacity [Figure 1]a. CT scan of chest showed heterodense mass with multiple areas of calcification in the pre-tracheal, left paratracheal, pre-carinal, sub carinal, right hilar and pre-vertebral regions causing extrinsic compression of the right main bronchus, without bony destruction. Minimal right para hilar consolidation was present [Figure 1]b.
The patient underwent CT-guided biopsy of the anterior mediastinal mass which showed a small round cell tumor which was CD 45, kappa light chains positive and CD 138 positive, consistent with a diagnosis of plasmacytoma [Figure 1]c. Bone marrow biopsy showed marrow involvement by atypical plasma cells (CD 138+, kappa light chain+). There were no bone lesions on skeletal survey. Serum protein electrophoresis for M-protein was negative. Serum free light chain (sFLC) showed a kappa: Lamda ratio of 100. The patient was diagnosed as multiple myeloma and was treated with 40 Gy RT to mediastinum and thalidomide-dexamethasone for 5 months. Post 5 months of treatment his chest X-ray showed >50% decrease in the size of mediastinal mass [Figure 1]d. His bone marrow is in remission and consolidation therapy is planned.
|Figure 1: (a) Chest X-ray showed mediastinal widening with tracheal deviation to the right side with left paratracheal nodularity (b) CT scan of chest showed hetrodense mass with multiple areas of calcification in the pre tracheal, left paratracheal, pre carinal, sub carinal, right hilar and pre vertebral regions causing mild extrinsic compression of the right main bronchus (c) Histopathology showing round cell tumor which are positive for CD 138 (d) Post-treatment imaging showing significant decrease in mediastinal mass|
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A 56-year-old male presented with chest discomfort of 1 month duration. General and systemic examination was within normal limits. Laboratory data showed hemoglobin of 12 g/dl, white cell count: 10800/μl, platelet count of 176000/μl and ESR was 50 mm in 1 st hour. Biochemical parameters were normal.
Chest X-ray showed right lower para tracheal opacity [Figure 2]a. CT scan of chest [Figure 2]b showed right para vertebral soft tissue mass extending and abutting the posterior mediastinum causing bony destruction of the underlying D3-D4 vertebral bodies and adjacent costo-vertebral junction. Biopsy showed uniform round cells with eccentric nucleus and perinuclear halo (CD38+, CD138+) suggesting plasmacytoma [Figure 2]c. Bone marrow biopsy was normal.
Magnetic resonance imaging of the dorsal spine showed intraspinal extension of the mass causing cord compression [Figure 2]d and e. Serum electrophoresis showed an M spike of 2.3 g/dl. Skeletal survey revealed a lytic lesion in the skull [Figure 2]f. A diagnosis of multiple myeloma was made. Treatment with radiation to paravertebral plasmacytoma and oral lenalidomide and dexamethasone was initiated.
|Figure 2: (a) Chest X-ray showed right lower para tracheal nodularity (b) CT scan of chest reveals evidence of a right para vertebral soft tissue mass extending and abutting posterior mediastinum causing bony destruction of the underlying D3-D4 vertebral bodies and adjacent costo vertebral junction (c) Biopsy of mass was showing roundcell tumor with eccentric nucleus and perinuclear halos suggestive of plasmacytoma (d and e) MRI of the dorsal spine showed evidence of intraspinal extension of the mass causing mild cord compression (f) X-ray of skull revealed punched out lytic lesion|
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| > Discussion|| |
Mediastinal widening is a common radiological finding that is encountered by physicians. Common differential diagnoses include lymphoma, thymoma, retrosternal goiter, germ cell tumor, neurogenic tumor, pericardial cyst, and aortic aneurysm.
It is very unusual for myeloma to present with a mediastinal mass. In a study of 958 cases of multiple myeloma, intrathoracic EMP was seen in only eleven (1%) of all the patients.  Others have reported varying patterns of thoracic involvement in multiple myeloma including lung masses, pulmonary nodules, diffuse reticulo-nodular infiltration, lymph node enlargement, mediastinal masses, nodular pleural thickening and pleural effusion and trachea-bronchial infiltration.  There is one other report of solitary plasmacytoma causing tracheal compression and presenting as stridor (as in case-1 above). 
Only 5% of patients with EMPs have co-existent multiple myeloma.  In our first case of mediastinal plasmacytoma, bone marrow involvement was present and serum free light chain was elevated. In our second case, M-spike was present in serum electrophoresis and skeletal survey revealed lytic lesions in skull, thus establishing co-existent multiple myeloma in both cases.
After the diagnosis of plasmacytoma aggressive search for multiple myeloma is vital as the management is entirely different for both types of plasma cell dyscrasias. Plasmacytomas are treated with radiotherapy, surgery or both.  Chemotherapy may be considered for patients with refractory or relapsed disease whereas multiple myeloma is mostly treated with chemotherapy. 
In conclusion, both these patients lacked other common clinical features of myeloma such as fatigue (due to anemia) or bone-pain or renal failure. Only laboratory work-up initiated after the diagnosis of mediastinal plasmacytoma could establish the presence of an underlying myeloma. We present these cases for their rarity and to sensitize clinicians about unusual causes of mediastinal masses.
| > References|| |
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