PMC8232835_01
Initial pathologic examination of BM biopsy. (A) H&E-stained sections show a hypercellular BM. (B) On high power, the cells show a characteristic fried egg appearance. (C) They are CD20 diffusely positive. (D) Aspirate smears were paucicellular and pauci-spicular. (E) Peripheral blood showed occasional circulating hairy cells. (F and G) The BM showed the CD20+ cells were diffusely and strongly CD5+ and CD23+ (H and I) while being negative for CD25 and annexin A1. BM, bone marrow; H&E, hematoxylin and eosin.
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PMC8232835_01_po-5-po.20.00518-g001.jpg
fig1
Workup at our institution was initiated and peripheral blood flow cytometry revealed an abnormal B-cell population with immunophenotype summarized in Figure 1.