Multiple myeloma presenting as an intracranial plasmacytoma: a case report
1Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231, Shimizu-Ku, Shizuoka, 424-8636, Japan.
Insights
Multiple myeloma rarely presents as an intracranial plasmacytoma. This case highlights the importance of considering multiple myeloma in patients with unexplained brain tumors, even without detectable M protein in blood.
Area of Science:
- Neurology
- Oncology
- Pathology
Background:
- Multiple myeloma, a plasma cell malignancy, typically affects bone marrow.
- Intracranial plasmacytoma as an initial manifestation of multiple myeloma is exceptionally rare.
Purpose of the Study:
- To report a rare case of multiple myeloma initially presenting as an intracranial plasmacytoma.
- To discuss the diagnostic challenges and clinical implications of such presentations.
Main Methods:
- Case report of an 81-year-old woman with gait disturbance.
- Diagnostic workup included neuroimaging (CT, MRI), histopathology, immunohistochemistry, and laboratory tests.
- Treatment involved surgical excision followed by adjuvant chemoradiation.
Main Results:
- An intracranial mass was surgically removed and pathologically diagnosed as plasmacytoma.
- The patient achieved remission but later developed multiple bone metastases, confirming multiple myeloma.
- Bence-Jones protein (IgG kappa-chain) was detected in urine, but M protein was absent in blood.
Conclusions:
- Multiple myeloma can present as an intracranial plasmacytoma, posing diagnostic challenges.
- Urine Bence-Jones protein analysis is crucial when M protein is undetectable in serum.
- This case underscores the need for comprehensive evaluation in atypical myeloma presentations.
Abstract:
Multiple myeloma presenting as an intracranial tumor (plasmacytoma) is very rare. An 81-year-old woman was admitted to our hospital because of gait disturbance. A blood laboratory test revealed a mildly increased lactate dehydrogenase (236 IU/L) and glucose (121 mg/dl). Blood protein fractions were normal. Brain computed tomography and magnetic resonance imaging revealed an intracranial mass (5 x 4 x 3 cm) in the brain base next to the clavus, and it was clinically diagnosed as chordoma. An excision of the brain tumor was performed. Imaging modalities including ultrasound, x-ray, computed tomography, magnetic resonance imaging and positron emission tomography did not reveal any tumors other than the brain tumor. The tumor was soft, fragile, and bloody. Microscopically, a monotonous proliferation of atypical plasma cells with hyperchromatic nuclei was recognized. Histochemically, the tumor cells were pyroninophilic and the congo-red stain revealed amyloidosis. Immunohistochemically, the tumor cells were positive for kappa-chain and negative for cytokeratin, epithelial membrane antigen, vimentin, CD45, CD20, CD45RO, lambda-chain, IgM, IgA, IgG, synaptophysin, chromogranin, S100 protein, desmin, alpha-smooth muscle antigen, myoglobin, p53 protein, and glial fibrillary acidic protein. The Ki-67 labeling was 11%. Intracranial plasmacytoma was pathologically diagnosed. The patient was treated by adjuvant chemoradiation, and entered into the complete remission stage. However, multiple metastases emerged in the vertebral bones and ribs six months after the remission. A diagnosis of multiple myeloma was made. The urine revealed Bence-Jones protein of monoclonal IgG kappa-chain type, but blood M protein was not recognized. The patient's condition gradually deteriorated. The patient died of respiratory failure due to bronchopneumonia 18 months after the admission. The present case indicates that multiple myeloma may manifest as an intracranial brain tumor (plasmacytoma).
