neuroplex
New York Association of Neuropathologists
4/26/2005 Case 3: Primary intracerebral plasmacytoma
Clinical History:
83 year old woman with remote history of gastric carcinoma and recent history (within one year)
of ductal breast carcinoma experienced an episode of confusion with loss of speech. She
recovered from this. An MRI scan showed a 1 cm enhancing nodule in the left parietal lobe with
surrounding T2 abnormality (called "edema") and mass effect; and a second, smaller lesion in the
right insula. Workup for other sites of metastatic disease was all negative. A stereotactic biopsy
of the left parietal mass was performed, and is represented on the slides distributed.
Diagnostic Notes:
The biopsy showed brain tissue infiltrated and replaced by a mass of
relatively small cells; these were a fairly homogeneous population of plasma
cells, some mature, some immature. There was a hint of perivascular cuff
formation resembling lymphoma in the brain, and there was some more diffuse
infiltration as single cells into the brain. Focally there were hemosiderin
deposits.
The diagnosis was straightforward if unusual: a primary CNS plasmacytoma, and
clearly neither metastatic gastric carcinoma nor metastatic breast carcinoma.
Immunostains for light chains had excessive background, but NYU
Hematopathology did in-situ hybridization for kappa and lambda light chain
mRNA and showed that the mass was a clonal population of kappa-positive plasma
cells. The diagnosis is thus verified as Plasmacytoma. There are very few
case reports of primary intracerebral plasmacytoma; they indicate a relatively
favorable prognosis, with no evidence of spread as multiple myeloma later. In
this patient an extensive workup disclosed no other evidence of disease, and
she remained well six months after diagnosis of the intracerebral lesion.
