Plasma Cell Leukemia – Facts and Controversies: More Questions than Answers?

Abstract

Plasma cell leukemia (PCL) is an aggressive hematological malignancy characterized by an uncontrolled clonal proliferation of plasma cells (PCs) in the bone marrow and peripheral blood. PCL has been defined by an absolute number of circulating PCs exceeding 2.0 × 10 9 /L and/or >20% PCs in the total leucocyte count. It is classified as primary PCL, which develops de novo , and secondary PCL, occurring at the late and advanced stages of multiple myeloma (MM). Primary and secondary PCL are clinically and biologically two distinct entities. After the diagnosis, treatment should be immediate and should include a proteasome inhibitor and immunomodulator-based combination regimens as induction, followed by stem cell transplantation (SCT) in transplant-eligible individuals who have cleared the peripheral blood of circulating PCs. Due to the rarity of the condition, there have been very few clinical trials. Furthermore, virtually all of the myeloma trials exclude patients with active PCL. The evaluation of response has been defined by the International Myeloma Working Group and consists of both acute leukemia and MM criteria. With conventional chemotherapy, the prognosis of primary PCL has been ominous, with reported overall survival (OS) ranging from 6.8 to 12.6 months. The use of novel agents and autologous SCT appears to be associated with deeper response and an improved survival, although it still remains low. The PCL prognostic index provides a simple score to risk-stratify PCL. The prognosis of secondary PCL is extremely poor, with OS of only 1 month.

The Cytogenetic Profile of Primary and Secondary Plasma Cell Leukemia: Etiopathogenetic Perspectives, Prognostic Impact and Clinical Relevance to Newly Diagnosed Multiple Myeloma with Differential Circulating Clonal Plasma Cells

“…PCL presents with unique features and a more aggressive clinical behavior when compared to MM. These differences include distinct molecular (both genetic and gene-expression profile), phenotypic and bone marrow (BM) microenvironmental features, a distinct distribution and proportion of cytogenetic abnormalities, higher tumor mass, extramedullary involvement, impaired renal function, increased lactate dehydrogenase (LDH) and β2-microglobulin, and more pronounced anemias and thrombocytopenias [ 3 , 5 , 9 , 10 , 11 , 12 ]. Moreover, several differences have also been reported between pPCL and sPCL, thus indicating that they should probably be evaluated as distinct clinical entities [ 13 , 14 , 15 ].…”

Plasma Cell Leukemia—Clinicopathological Profile from a Tertiary Care Center in Western India

“…Peijing et al described patients with PCL who had hepatomegaly (44%), splenomegaly (33%), or lymphadenopathy (22.7%). 10 11 12 In our series, 33% of patients had hepatomegaly, 37% had splenomegaly, and 21% had lymphadenopathy. Osteolytic lesions were less common in PC.…”

Plasma Cell Leukemia: An Aggressive Disease, a Cause of Diagnostic Error

“…The work-up is completed by a myelogram or bone marrow biopsy, serum protein electrophoresis with immunofixation and a biochemical assessment. Compared to MM, LP is more frequently responsible for anemia, thrombocytopenia, hypercalcemia, renal failure, and higher serum levels of LDH and ß2-microglobulin (a reflection of tumor mass) due to the aggressive course of the disease, including a higher tumor burden and a higher proliferation index (9) . Due to the delay in the specialized consultation, our patient presented a sudden deterioration of her clinical picture with a multi-organ involvement (renal, pulmonary, neurological and probably pulmonary) which was lifethreatening.…”