PMC6165604_01
Bone marrow biopsy. (a, b) Representative areas of hematoxylin and eosin-stained sections of the bone marrow biopsy ((a) 10x, (b) 40x). (c) Immunohistochemical (IHC) staining for the erythroid marker CD71 (10x). (d) IHC stain for the myeloid marker MPO (20x).
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Due to the polycythemia having no obvious etiology, a bone marrow aspiration and biopsy were performed (Figures 1(a) and 1(b)). The core biopsy showing a markedly decreased myeloid: erythroid ratio with CD71-positive erythroid precursors comprising ~80% of marrow cellularity (Figure 1(c)) and MPO-positive myeloid cells comprising < 10% of cells (Figure 1(d)).
Evidence of a plasma cell neoplasm. (a) Touch prep of the bone marrow biopsy showing numerous plasma cells (arrow, 50x). (b) IHC staining for the plasma cell marker CD138 (10x). (c) Flow cytometric dot plot of CD38/CD138-positive plasma cells from the bone marrow aspirate showing a monotypic lambda-restricted plasma cell population.
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Figure 2(a)), and CD138 immunohistochemical staining highlighted the increased plasma cells arranged in clusters in the core biopsy (~15% of cellularity, Figure 2(b)). Flow cytometry demonstrated the bone marrow aspirate contained a monotypic lambda-restricted CD38/CD138-positive plasma cell population (Figure 2(c)).