Two cases of nonsecretory multiple myeloma presenting as primary plasma cell leukemia

Oligosecretory Primary Plasma Cell Leukemia with Atypical Morphological Abnormality

Plasma cell leukemia (PCL) is a rare variant of multiple myeloma. The detection of plasma cells in the peripheral blood and monoclonal protein in the serum or urine is important for the diagnosis of PCL. However, it is sometimes difficult to diagnose PCL in patients with atypical plasma cell morphology and/or those without detectable monoclonal protein. We herein report a case of oligosecretory PCL showing atypical morphology in leukemic cells with a convoluted nucleus and basophilic cytoplasm but without detectable monoclonal protein, except for serum free light chain. A flow cytometric analysis and pathological analysis were useful for the early diagnosis of PCL.

Utility of hematology analyzer and flow cytometry in timely and correct detection of circulating plasma cells: Report of three cases

BACKGROUND

Circulating neoplastic plasma cells (PCs) are a common feature between classical plasma cell myeloma (PCM) and its aggressive variant, plasma cell leukemia (PCL), with their early suspicion and detection being of clinical importance for prognostic and diagnostic purposes.

METHODS

Morphological and flow cytometric enumeration and characterization of peripheral blood (PB) neoplastic PCs were performed in 3 PCM patients after complete blood count (CBC) evaluation.

RESULTS

Early suspicion of circulating PCs by initial CBC scatter plots and monocytosis led to morphological enumeration of PCs, with low level of concordance between morphologists. Flow cytometric PB analysis permitted accurate quantification and characterization of circulating clonal PCs.

CONCLUSIONS

CBC findings can prompt early suspicion of circulating PCs in PCM patients leading to early and accurate flow cytometric analysis of clonal PCs in addition to morphological PB evaluation. The suggested combined approach proved to be most important in the PCL case with discordant morphological evaluations and marginal PC numbers according to current criteria. © 2016 International Clinical Cytometry Society.