Primary plasma cell leukemia- A rare entity
Plasma cell leukemia (PCL) is a rare and aggressive variant of multiple myeloma (MM) with a generally fulminant course. The disease entity arises in 1%‐4% of patients with MM. PCL is further classified as primary (pPCL) when the leukemic phase is present at diagnosis or as secondary (sPCL) when there is leukemic transformation of relapsed or refractory MM. Representing up to 60% of cases of PCL, pPCL poses a significant clinical challenge with dismal survival outcomes even when treated with novel chemotherapy agents and autologous stem cell transplantation.

This is a case of a 76‐year‐old African American woman with pPCL who was treated with early aggressive chemotherapy. While she did not meet Kyle's criteria, morphological, immunophenotypic and immunohistochemical studies, and overall clinical presentation support the diagnosis. She was initially treated with dexamethasone followed by bortezomib, cyclophosphamide, and daratumumab for 3 cycles with good response. Repeat serum protein electrophoresis (SPEP) and peripheral flow cytometry demonstrated no evidence for clonal B‐cell population, abnormal T‐cell population, or increased blast population.

This case illustrates the application of daratumumab as part of a novel agent‐based regimen as a first‐line treatment of pPCL to impart a deeper and more rapid clinical response and the need for a less stringent criteria in its diagnosis.

Source: Clin Case Rep. 2019;00:1–7

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