Figure 1. Initial bone marrow biopsy: The bone marrow is markedly hypercellular and left-shifted, with increased and abnormal megakaryocytes and lymphoid aggregates consistent with involvement by CLL (H&E).
Figure 2. Initial bone marrow biopsy: Left-shifted erythroid and myeloid cells (H&E).
Figure 3. Initial bone marrow biopsy: Immunohistochemistry for CD34 reveals increased blasts, comprising 10-15% of the cellularity.
Figure 4. Initial bone marrow biopsy: Immunohistochemistry for CD61 highlights dysplastic megakaryocytes.
Figure 5. Final bone marrow biopsy showing progression to pure erythroid leukemia: The markedly hypercellular bone marrow contains sheets of large blasts, as well as persistent CLL aggregates and dysplastic megakaryocytes (H&E).
Figure 6. Final bone marrow biopsy showing progression to pure erythroid leukemia: The blasts contain vesicular chromatin, multiple nucleoli, and smooth, amphophilic chromatin, consistent with erythroblasts (H&E).
Figure 7. Final bone marrow biopsy showing progression to pure erythroid leukemia: By immunohistochemistry, the blasts are glycophorin positive, confirming erythroid lineage.
Figure 8. Final bone marrow biopsy showing progression to pure erythroid leukemia: The background small lymphocytes are PAX5 positive, consistent with CLL.
Figure 9. Final bone marrow biopsy showing progression to pure erythroid leukemia: The bone marrow aspirate contains numerous large erythroid blasts with deeply basophilic cytoplasm, frequent cytoplasmic vacuoles, and often irregular and bizarre nuclei (Wright-Giemsa).