PMC7758647_01
Bone marrow biopsy. (A) Bone marrow core biopsy, hematoxylin and eosin (H&E) stain, 10x. Markedly hypercellular marrow (>90%) with diffuse atypical lymphoid Infiltrate (arrow). (B) Bone marrow biopsy, H&E stain, 50x. Sheets of atypical medium-sized lymphoid cells (arrow). (C) Positive for CD20 immunohistochemical stain showing strong membrane positivity (arrow) 50x. (D) Ki-67 immunohistochemical stain very high (>90%). Arrow indicating strong nuclear staining positivity 50x.
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PMC7758647_01_10.1177_2324709620982765-fig1.jpg
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Then, bone marrow biopsy was performed, which showed markedly hypercellular marrow with sheets of atypical medium-sized lymphoid cells, and no evidence of hemophagocytosis (Figure 1).