A 68-year-old woman with a medical history of multiple myeloma, hypertension, and hypothyroidism was admitted to the hospital for fever of unknown origin and generalized malaise. Her multiple myeloma was reportedly in remission and she had previously undergone chemotherapy.
Stephen Waite, MD
Richard Batz, MD
Caren Jahre, MD
of the Department of Radiology, Lenox Hill Hospital, New York,
A 68-year-old woman with a medical history of multiple myeloma,
hypertension, and hypothyroidism was admitted to the hospital for
fever of unknown origin and generalized malaise. Her multiple
myeloma was reportedly in remission and she had previously
Physical examination demonstrated a nonfocal neurologic
examination. Laboratory findings were significant for
thrombocytopenia, anemia, and hypercalcemia. A few days after
admission, the patient acutely developed an expressive aphasia and
incontinence, which prompted a computed tomography (CT) scan of the
head (Figures 1 and 2).
A head CT demonstrated a 2.4 * 3 cm hyperdense extra-axial left
frontal mass with a rim of greater hyperdensity (Figure 1). There
is a significant amount of surrounding edema and associated
transfalcine herniation. There was bone destruction at the site of
the lesion as well as multiple small uniform lytic lesions
throughout the calvarium (Figure 2).
A subsequent MRI examination demonstrated the mass to be
extra-axial, hypointense on T1-weighted images (Figure 3), and
isointense on fluid-attenuated inversion recovery (FLAIR) (Figure
4) and T2-weighted images (not shown). There is a thin rim of
hyperintensity on T1-weighted images and hypointensity on T2
weighted images. There was intense enhancement with an associated
dural tail (Figure 5), as well as extensive vasogenic edema (Figure
Subsequent surgical resection revealed an extra-axial mass
consisting of immature plasma cells that extended into the brain,
consistent with a plasmacytoma. The adjacent calvarium was invaded
Multiple myeloma is the most common primary malignant bone tumor
and accounts for approximately 27% of biopsied bone tumors. It is
the result of malignant proliferation of plasma cells that
infiltrate the bone marrow. In the classic form, the skeleton
contains multiple permeative lesions that are filled by masses of
neoplastic plasma cells. Areas of increased osteoclastic activity
surround these focal collections of plasma cells. The radiographic
hallmark is the sharply circumscribed osteolytic defect. These
lesions are multiple, round, and purely lytic involving virtually
any bone. A plasmacytoma is a localized form of plasma cell
Neurologic complications occur in up to 40% of patients with
Often patients have neurologic symptoms from metabolic
disturbances, such as hypercalcemia and hyperviscosity states.
Often the mechanical effects of local tumor or displaced bone
compress neural structures such as the spinal cord.
Other neurologic manifestations of myeloma include diffuse
leptomeningeal disease. Intracranial involvement by multiple
myeloma, however, is an uncommon finding.
It can manifest as a solitary tumor in the dura mater without
invasion of the brain parenchyma, an intra-axial tumor without
attachment to the dura mater or bone, or an invasive tumor that may
grow from the dura mater into the brain.
The most common sites of intracranial plasmacytoma are the body of
the sphenoid bone, juxtasellar region, petrous apex, cerebral
convexity, or falx region.
The typical clinical presentation of an intracranial
plasmacytoma is that of an intracranial mass with focal
neurological signs, seizures, or increased intracranial pressure,
although there are no pathognomonic clinical features.
The presence of abnormal serum or cerebrospinal fluid (CSF)
immunoglobulins in electrophoresis studies has been reported in
intracranial plasmacytomas. Monitoring the level of CSF paraprotein
is thought to serve as a marker for tumor recurrence and a decrease
in the level is to be expected postoperatively.
Plasmacytomas are seen on CT examination as isodense to
hyperdense lesions that homogeneously enhance after administration
of a contrast agent. On MRI, these lesions are hypointense to
isointense on T1-weighted images and usually hyperintense on
T2-weighted images with dense uniform enhancement after gadolinium
Focal calcification or bone erosion without sclerosis may be seen.
Spontaneous hemorrhage into an intracranial plasmacytoma has also
The radiologic signs are not specific and may mimic a
meningioma, lymphoma, metastasis, and sarcoma
; however, the presence of osteolytic lesions is thought to suggest
a plasmacytoma, as meningiomas more often produce a hyperostotic
reaction. Plasmacytomas are also more often hyperintense to muscle
on T2-weighted images possibly because of intracellular
Meningiomas, on the other hand, are usually isointense on all pulse
This case of intracranial plasmacytoma manifested as a
hyperdense lesion with intense enhancement, both classic findings.
It is, however, atypical in that it was isointense on FLAIR and
T2-weighted images. It was associated with a lytic lesion,
suggesting the possibility of a plasmacytoma versus the much more
common meningioma, which is usually associated with
It is important to note that this patient's intracranial
plasmacytoma developed as part of the diffuse plasmacytic bony
involvement of multiple myeloma. This is important because patients
with a solitary intracranial plasmacytoma have a more favorable
clinical course. The finding of an intracranial plasmacytoma
therefore necessitates looking for systemic disease; and if
isolated, follow-up is important, as these lesions often terminate
in multiple myeloma.
If the preoperative diagnosis is a solitary intracranial
plasmacytoma, the current treatment of choice is surgical removal
and/or radiation therapy. These tumors are, in general,
radiosensitive and regress in almost every case after local
irradiation. Chemotherapy is suggested for systemic disease.
Although rare, an intracranial plasmacytoma should be in the
differential diagnosis of an extra-axial mass, especially in
patients with multiple myeloma or with an associated calvarial