multiple myeloma ( mm ) is a neoplasm of plasma cells accounting for 1015% of hematopoietic neoplasms .
it is more common in people of african descent , occurring twice as frequently compared to caucasians .
plasma cell leukemia ( pcl ) is a very rare type of mm characterized by high numbers ( > 20% ) of circulating plasma cells in the peripheral blood .
it comprises of an estimated 24% of cases of mm   and is an aggressive disease with poor prognosis .
the majority of cases occur de novo as primary pcl but it may also occur as leukemic transformation of underlying mm . because of the rarity of this disease , knowledge of its presentation and clinical course has been largely dependent on small studies and case reports .
the clinical presentation typically involves symptoms attributed to end organ damage seen in mm ( hypercalcemia , renal failure , anemia , and lytic bone lesions ) or to leukemia ( leukocytosis , thrombocytopenia and organomegaly ) .
we report a case of pcl with atypical presentation as a chest wall mass and discuss the diagnostic approach as well as treatment options .
a 65-year - old african - american male with a history of type 2 diabetes mellitus and inguinal and abdominal wall hernia presented with complaints of abdominal pain located in the left inguinal region , brought on by heavy lifting .
examination was significant for pallor , hepatomegaly and mild abdominal tenderness at the site of the inguinal hernia .
1a ) and a left chest wall mass with destruction of the underlying rib ( fig . 
an ultrasound - guided core needle biopsy of the chest mass , showed a diffuse monotonous population of small to medium - sized lymphocytes with plasmacytoid features ( fig .  2 ) .
the tumor cells were positive for cd138 and cd56 with monoclonal lambda restriction by in situ hybridization and showed a high proliferation index with ki67 ( 60% ) .
laboratory investigation was significant for elevated serum calcium of 12.2 g / dl ( reference 8.510.6 ) with normal parathyroid hormone level and evidence of acute renal failure [ creatinine 1.9 mg / dl ( reference 0.61.2 ) ] .
a complete blood count revealed mild leukocytosis [ 11.2  10/l ( reference 3.210.6  10 ) ] , macrocytic anemia with a hemoglobin of 8.0 g / dl ( reference 14.617.8 ) and mean corpuscular volume 101.9 fl ( reference 7794 ) .
serum protein electrophoresis and immunofixation showed a monoclonal spike with igg lambda , and quantitative igg levels were markedly elevated at 3,139 mg / dl ( reference 7911,643 ) .
a review of his peripheral blood smear showed 2535% circulating atypical lymphocytes with plasmacytoid features ( fig . 
3 ) , confirmed to be neoplastic plasma cells by flow cytometry and consistent with pcl . a bone marrow biopsy revealed marked infiltration with monoclonal plasma cells comprising > 50% of total bone marrow cellularity .
prior to the initiation of chemotherapy , the patient spontaneously developed hyperkalemia , worsening renal failure ; creatinine 3.2 mg / dl and elevated uric acid to 8.9 mg / dl ( reference 48.5 ) , suggestive of tumor lysis syndrome . he was managed with i.v .
the patient was referred for clinical trial where he was given induction chemotherapy with cybord ( cyclophosphamide , bortezomib , and dexamethasone ) on days 1 , 8 , 15 , and 22 of each 28-day cycle for a total of 4 cycles .
pcl was first reported in 1906 in a patient who presented with bone pain , a palpable rib mass , rib fractures , anemia , and splenomegaly [ 5 , 6 ] .
interestingly , this parallels our patient , in whom pcl was only diagnosed incidentally after presenting with abdominal pain , and then found to have hepatosplenomegaly and a neoplastic chest wall mass . although pcl lies in the spectrum of plasma cell dyscrasias ( of which mm is most common ) , there are some distinguishing features of the disease .
a review of the literature revealed cases manifesting as lymphadenopathy , hepatomegaly , splenomegaly , leptomeningeal myelomatosis , and soft tissue tumors [ 6 , 7 ] . in contrast ,
bone involvement with resultant lytic lesions , bone pain and pathological fractures is the predominant feature in mm .
patients with pcl are usually younger with a median age of 55 , whereas that for mm patients is 65 . the diagnosis of pcl is based on laboratory parameters . according to the consensus statement by the international myeloma working group
, pcl is defined by the presence of > 20% circulating plasma cells and/or an absolute plasma cell count > 2  10/l . as the diagnosis hinges on establishing an increased number of plasma cells in the peripheral blood , it is important to note that circulating plasma cells in pcl are often small with scant cytoplasm resembling plasmacytoid lymphocytes , and can easily be missed on automated differentials , especially when the white blood cell count is only minimally elevated . in the setting of organomegaly , soft tissue mass and hypercalcemia , serum and urine protein electrophoresis with immunofixation should be obtained to identify a monoclonal immunoglobulin . a careful review of the peripheral smear
should then be performed with peripheral blood flow cytometry to confirm the diagnosis of pcl .
a bone marrow biopsy with cytogenetics should be done in all patients diagnosed with pcl .
pcl is a highly aggressive tumor , with a high disease burden and proliferation index . as a result ,
this has been reported after commencing chemotherapy , but it may occur , as with our patient , even prior to chemotherapy .
it is important to identify patients who are at risk and closely monitor for markers of cell lysis : elevated serum potassium , lactate dehydrogenase and phosphorus , and a fall in serum calcium .
elevated uric acid levels can cause uric acid nephropathy , a predominant cause of acute renal failure in tumor lysis syndrome . due to the rare nature of pcl
, there is no standard treatment as randomized studies are not available and treatment data are extrapolated from mm studies .
the clinical outcome following chemotherapy with conventional agents has been shown to be much worse in pcl compared to mm .
new therapeutic strategies utilizing agents such as lenalidomide , bortezomib , and dexamethasone ( rvd ) , melphalan , prednisone , bortezomib , and thalidomide ( vmpt ) and bortezomib , thalidomide , and dexamethasone ( vtd ) have shown encouraging outcomes .
the overall prognosis is poor with a median survival of 611 months [ 8 , 10 ] , but some improvements in outcomes have been shown with newer therapies and stem cell transplantation . in a study of 445 patients with primary pcl , using the seer database and comparing overall survival in patients diagnosed between 1973 and 2005 to those diagnosed between 2006 and 2009 , there was an increase in overall survival from 5 to 12 months . .
since virtually all patients with pcl who attain a complete remission develop relapse , maintenance chemotherapy should be considered [ 12 , 13 ] .
agents such as lenalidomide , bortezomib , and thalidomide have been used for maintenance therapy . moreover , because of the high rate of recurrence and poor outcome with chemotherapy alone , consolidation with hematopoietic stem cell transplant provides the best hope for remaining in complete remission .
finally , patients with pcl , whenever possible , should be offered the opportunity to participate in clinical trials .
prompt diagnostic evaluation of a chest wall mass followed by peripheral smear evaluation led to timely diagnosis of pcl and early initiation of therapy .
pcl has varied clinical presentation ; as such , increased awareness and thorough evaluation with particular attention to the peripheral smear is paramount to establishing the diagnosis .
tumor lysis syndrome can complicate this aggressive disease ; therefore , there should be close monitoring of renal function .
due to the low prevalence of pcl , the chemotherapy regimens used are largely based on those used for mm .
it is important to report outcomes of therapies / regimens used to help establish guidelines for the management of pcl , pending a randomized clinical trial .
patients should also get early referral to a bone marrow transplant center , as there is a higher likelihood of achieving and maintaining complete remission with combined chemotherapy followed by hematopoietic stem cell transplantation .
the authors state no conflict of interests and have received no payment in the preparation of this paper .
 plasma cell leukemia ( pcl ) is an uncommon neoplasm of plasma cells , with an aggressive clinical course and poor outcome , even with current standard of care . 
 it can occur either de novo ( primary pcl ) or as a progression of multiple myeloma ( mm ) . 
 this disease has unique diagnostic criteria but certain genetic markers and clinical features may overlap with mm . 
 due to the low prevalence of pcl , guidelines on its management are extrapolated from the management of mm and based on small retrospective studies and cases reports / series . 
 we present an interesting case of pcl in a middle - aged african - american male , who was diagnosed incidentally after chest wall imaging for an unrelated complaint . 
 the diagnostic approach , management and outcomes of pcl are discussed . 
Introduction
Case Report
Discussion
Conclusion
Statement of Ethics
Disclosure Statement