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. (C) 2016 International Clinical Cytometry Society