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).