Figure 4. High-power electronic microscopy.

The image shows abnormal lymphoid cells with medium to large-sized ovoid nuclei, delicate chromatin, prominent nucleoli, and increased basophilic cytoplasm (blue arrow). A difference in cell size can be appreciated when comparing the normal-sized lymphocytes (yellow arrow) to the pathologic lymphoid cells. This phenomenon termed "Richters transformation" demonstrates the shift from normal-sized lymphocytes seen in chronic lymphoblastic leukemia into larger cells observed in diffuse large B-cell lymphoma