Indian J Hematol Blood Transfus 25(2):81–83 81
Indian J Hematol Blood Transfus 25(2):81–83
Primary non-secretory plasma cell leukemia with atypical
morphology – a case report
T. Dadu · A. Rangan · A. Handoo · M. Bhargava
Received: 18 January 2009 / Accepted: 2 March 2009
© Indian Society of Hematology and Transfusion Medicine 2009
Abstract Only one case of primary non-secretory plasma
cell leukemia with atypical morphology has been reported
thus far. Here we report another such case of plasma cell
leukemia diagnosed on fl ow cytometry, as morphological
heterogeneity and lack of monoclonal immunoglobulins in
both serum and urine, made it diffi cult to come to a conclu-
sive diagnosis based purely on morphology.
Keywords Plasma cell leukemia · Multiple myeloma ·
Flow cytometry · Electrophoresis
Plasma cell leukemia (PCL) is a rare and aggressive vari-
ant of multiple myeloma with poor prognosis characterized
by peripheral blood involvement. The exact incidence of
primary plasma cell leukemia is believed to be less than 1
case/million . In certain PCL cases, the leukemic cells
are more diffi cult to identify without electron microscope
 or immunohistochemical/immunophenotypic studies.
The diagnosis may be made diffi cult further by the non-
secretory nature of plasma cell leukemia. Only 1 case of
primary non secretory plasma cell leukemia with atypical
morphology has been reported . Here, we report another
case of primary non-secretory plasma cell leukemia with
A 60-year-old lady presented with weakness and low back-
ache for 2 months. Physical examination revealed no abnor-
mality, other than bony tenderness in the back.
Blood counts were - Hb: 11.5 g/dl, TLC: 38,800/μl
with 57% atypical lymphoid cells and platelets: 2,50,000/
μl. Other abnormal laboratory fi ndings were raised ESR
(65 mm at the end of fi rst hour), increased lactic dehydro-
genase (650U/L) and β2 microglobulin (16.4 mg/l). No liver
or kidney dysfunction was detected by serum biochemical
determinations. Magnetic resonance imaging revealed par-
tial compression collapse of D9 vertebra.
Bone marrow showed 58% small to medium sized atypi-
cal lymphoid cells with a heterogenous morphology. Few of
them had bipolar distribution of cytoplasm, and some had a
lympho-plasmacytoid appearance (Figs. 1 and 2). Few large
abnormal cells were also seen. The possibility of infi ltra-
tion by a lympho-plasmacytoid lymphoma with spill into
peripheral blood was thought of based on morphology.
T. Dadu · A. Rangan · A. Handoo · M. Bhargava
Department of Hematology,
Sir Ganga Ram Hospital,
Rajinder Nagar, New Delhi, India
T. Dadu (?)
82 Indian J Hematol Blood Transfus 25(2):81–83
However, serum protein electrophoresis (SPE), urine
protein electrophoresis (UPE) and immunofi xation electro-
phoresis (IFE) showed no monoclonal proteins.
Flowcytometric immunophenotyping of peripheral
blood cells was suggested to confi rm the diagnosis. Flow-
cytometric analysis was performed on Beckman Coulter
EPICS XL instrument. Surprisingly, the analysis disclosed
that the abnormal cells were plasma cells. 60% of the cells
were moderately bright for CD38 with absence of CD45,
CD19, CD20, CD10, CD56 & surface κ/λ, hence ruling out
infi ltration by a lymphoma (Fig. 3).
Based on fl ow cytometry, SPE, UPE and IFE, a diagno-
sis of a primary non-secretory plasma cell leukemia with
atypical morphology was made.
Morphological heterogeneity, including various immature
features, in atypical plasma cell leukemias sometimes
makes the diagnosis of PCL diffi cult and may require an
immunohistochemistry or electron microscopic examina-
tion to establish a defi nitive diagnosis . The diagnosis
may be made diffi cult further by the non-secretory (absence
of M component) nature of the PCL .
Only one case of PNSPCL with atypical morphology has
been reported so far . Absence of a monoclonal protein
in the serum and urine of patients with non-secretory PCL
may be a result of (i) an inability to excrete immunoglobin
(non-secretors) (ii) low synthetic capacity for immunoglo-
bin (non-producers) (iii) increased intracellular degrada-
tion, or (iv) rapid extracellular degradation of abnormal
The molecular basis of non-seceretory myeloma could
be due to loss of light chain production (in non-producers)
 or mutations that causes absence of cysteines required
for disulfi de bonds. This results in abnormal misfolded light
chains, which get retained in the plasma cells due to mis-
folding and are lysed.
Fig. 1 Atypical plasma cells with bipolar projections
Fig. 2 Morphological heterogeneity with abnormal lymphoid
and lympho-plasmacytoid cells
Fig. 3 Flow cytometry scattergrams showing bright surface CD 38 positivity and negativity for CD 45, CD 56, CD 19, CD10, CD 20
and surface κ/λ
Indian J Hematol Blood Transfus 25(2):81–83 83 Download full-text
In the present case, most of the cells exhibited an atypi-
cal morphology which made it diffi cult to reach a defi nitive
diagnosis. Some cases of primary plasma cell leukemias
with atypical morphological features (cleaved, monocytoid
or multilobated nuclei) , hairy cell morphology [2, 8]
and lympho-plasmacytoid morphology, have been reported,
however these were secretory in nature. These morphologi-
cal characteristics seem to be related to a worse prognosis
than the usual well-differentiated myeloma . Also in our
case, the cells were non-secretory in nature, which is again
a rarity, as very few cases of primary non-secretory PCL
have been reported .
Considerable overlap of immunophenotypic markers ex-
ists between multiple myeloma and plasma cell leukemia.
However, signifi cant differences in antigen expression have
been identifi ed which help to differentiate the two variants.
Plasma cells in PCL frequently display a more immature
phenotype. Immunophenotypically, plasma cells in PCL
show the following pattern: CD38+, CD138+, CD79a+,
cytoplasmic Ig+, CD20-/+, CD19 -, CD45-, CD 56-,
surface Ig- . Expression of pan-B cell antigen CD20 has
been shown in 50% of PCL cases compared to 17% of mul-
tiple myeloma cases. In addition, neoplastic cells in marrow
and peripheral blood in PCL typically do not express CD56,
which is considered to have an important role in anchoring
plasma cells to bone marrow stroma.
Our fi nal diagnosis was made on fl ow cytometric
immunophenotyping that showed the cells to be bright
surface CD38 positive and negative for CD45, CD19,
CD20, CD10, CD56 and surface κ/λ.
Accurate diagnosis of primary PCL is essential, as it is
an aggressive disease with a short median survival of 2–6
months , with poor response to chemotherapy.
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