Magnetic resonance imaging in the staging of solitary plasmacytoma of bone.
OBJECTIVE
To assess prospectively the role of magnetic resonance (MR) imaging in the staging of patients with a solitary bone plasmacytoma (SBP).


METHODS
Twelve consecutive patients with an apparent SBP underwent MR imaging of both the primary tumor and the thoracic and lumbosacral spine to seek additional foci of marrow involvement that might have been undetected by standard skeletal survey. All patients received megavoltage irradiation (total dose, 40 Gy) to the primary lesion.


RESULTS
MR imaging of the thoracic and lumbosacral spine showed additional foci of marrow replacement in four of 12 patients, with signal characteristics identical to those of the primary tumor. In all four patients, the abnormal protein persisted at greater than 50% of the pretreatment value following radiation treatment. In contrast, the myeloma protein disappeared or was reduced by greater than 50% in five of the six patients with secretory disease and without additional marrow abnormalities. One of four patients progressed to multiple myeloma 10 months after diagnosis with new lesions on conventional radiographs in the same areas as detected previously by MR imaging.


CONCLUSIONS
Four of 12 patients considered to have a SBP by standard criteria may have been understaged, because MR imaging showed additional marrow abnormalities consistent with myeloma. MR imaging of the spine may contribute to the initial staging of SBP, especially since some patients may be cured with radiotherapy.
Moulopoulos
L A
LA
Department of Diagnostic Imaging, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Dimopoulos
M A
MA
Weber
D
D
Fuller
L
L
Libshitz
H I
HI
Alexanian
R
R
D000328:Adult; D000368:Aged; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D010954:Plasmacytoma / Q000473:pathology*; D011446:Prospective Studies; D013125:Spinal Neoplasms / Q000473:pathology*