A 37-year-old woman originally presented in 2003 with the gradual onset
of paresthesias and weakness of the lower extremities that had progressed
resulting in significant gait disturbance. An MRI of the thoracic spine
revealed a large paraspinal and intraspinal mass of T9 and T10 vertebral bodies
causing lytic destruction of the vertebrae with cord compression at T9 and T10
levels. She underwent partial resection of the mass and vertebrae to relieve
the cord compression and spine stabilization. Her surgical specimen pathology
was most consistent with plasmacytoma of the T9 and T10 vertebral bodies and
chronic inflammation suggestive of Castlemans disease of pleura.
The subsequent work up for the multiple myeloma, including the skeletal
survey and the bone marrow biopsy, were negative. She completed radiation
therapy with total dose of 4,500 cGy. Her lower extremity strength, neuropathy
and gait all markedly improved. The follow-up MRI six months later showed no
new lesions except for possible scar tissue at T10 area.
Four years later, while pregnant, she presented with a new right hip
pain. Her serum protein electrophoresis showed a new small IgG lambda
M-component. Work up for myeloma was unrevealing. Further imaging was delayed
because of pregnancy. She was managed expectantly as her hip pain spontaneously
resolved. She continued to have a small stable 0.3 gm/dL IgG lambda M-component
throughout the pregnancy.
Figure 1: Axial PET/CT images in the upper row demonstrate
hypermetabolic activity corresponding to the 3.7 x 1.6 mass with SUV of 14.2 in
left posterior 11th/12th intercostal space and left pararenal space,
inseparable from the left diaphragm. The left image is axial CT scan, the
middle image is corresponding PET image, the right image is fusion image
containing PET images displayed on a color scale and CT images displayed on a
gray scale. The lower row images are from the follow up PET/CT six months later
demonstrating a grossly stable 3.7 x 1.3 cm soft tissue mass in the same
location with decreased SUV of 10.1 from 14.2.
Courtesy of M Ghesani
The subsequent staging PET/CT after delivery revealed 3.7 cm 3 1.6 cm
mass with standard uptake value of 14.2 in left posterior 11th/12th intercostal
space and left pararenal space, inseparable from the left diaphragm. CT guided
biopsy confirmed recurrent plasmacytoma, which on immunohistochemistry was
CD138 positive, lambda positive, and CD20 negative. Once again, work up for
multiple myeloma, including the bone marrow biopsy, was negative. She underwent
a second radiation treatment with 4,500 cGy for her recurrent solitary
plasmacytoma. Two months later serum protein electrophoresis still had a small
but unquantifiable IgG lambda M-component. Re-staging PET/CT had a grossly
stable 3.7 cm 3 1.3 cm soft tissue mass in the same location with decreased
standard uptake value of 10.1 from 14.2. Currently the patient is under
Solitary plasmacytoma originating in the bone is defined as an isolated
lesion comprised of neoplastic cells that produce a single clone of the plasma
cells in the absence of other features of multiple myeloma. It is a rare
condition and constitutes only 5% of all plasma cell neoplasms. More than 50%
of patients with solitary plasmacytoma of the bone will progress to develop
multiple myeloma within the course of three to 10 years. The median overall
survival of patients is approximately 10 years. The conventional treatment for
the plasmacytoma of the bone is radiation therapy. The usual dose of 40 Gy to
50 Gy given for about four weeks produces local response rate of about 80% to
The prognostic factors for solitary plasmacytoma of the bone whether
before of after radiation therapy have not been established. A review of
solitary plasmacytoma was conducted by the Mayo Clinic in the attempt to better
define the clinical features and gross prognostic indicators of the disease.
The review showed that of 46 cases from the clinic 54% progressed to multiple
myeloma, 11% developed local recurrence, and only 2% developed new plasmacytoma
in the absence of multiple myeloma.
Adverse prognostic factors associated with higher relapse rates were age
older than 60, extra-axial skeletal lesions location, and tumors of more than 5
cm. The presence of M-protein at the time of diagnosis did not have a
prognostic value; however, after radiation therapy, persistent M-protein for
more than one year was a significant predictor of subsequent progression to
Figure 2: Images depicting the mass before and after radiation
therapy at a slightly different level than the one in Figure 1.
Courtesy of M Ghesani
A series of 60 patients evaluated at M.D. Anderson showed that
persistent M-protein was the only independent factor that was associated with
adverse outcome. The researchers recommended that patients should be monitored
frequently and considered for chemotherapy treatment when they either develop
symptoms or show an increase in M-protein level.
Later, the risk stratification model developed at the Mayo Clinic
identified two predictors: 1) persistent serum M-protein level > 0.5 g/dL,
and 2) abnormal free light chain ratio at the time of diagnosis. The model
established a five-year progression risk of 13% for low risk (zero), 26% for
intermediate risk (one) and 62% for high risk (two).
In the era of PET/CT, with regard to staging for plasma cell neoplasms,
a potential prognostic factor may be the presence of the persistent FDG
activity after definitive radiation therapy. A very small series of 11 patients
who had pre- and postradiotherapy PET/CT showed complete metabolic response in
eight patients, progressive disease in two patients and one patient, who
initially had no response, eventually developed a late response. Persistence or
slow resolution of FDG activity may play a role in the prognosis of the
solitary plasmacytoma and it certainly warrants further studies.
Liana Makarian, MD, is an Oncology Fellow at St Lukes-Roosevelt
Munir Ghesani, MD, is Associate Clinical Professor of Radiology at
Columbia University College of Physicians and Surgeons and Attending
Radiologist at St.Lukes-Roosevelt Medical Center.
Michael Grossbard, MD, is a Professor of Clinical Medicine, Columbia
University College of Physicians and Surgeons.
For more information:
- Dingli D. Blood. 2006; 108:1979-1983.
- Durie B. J Nucl Med. 2002;43:1457-1463.
- Frassica DA. Int J Radiat Oncol Biol Phys.
- Kin PJ. Int J Radiat Oncol Biol Phys.
- Wilder RB. Cancer. 2002;94:1523-1527.