Figure 1. Bone marrow biopsy at diagnosis (H&E, 100x). Hypercellular bone marrow with abundant monolobated megakaryocytes, in a background of dysplastic maturing erythroids and granulocytes.
Figure 2. Bone marrow biopsy at diagnosis (CD34, 200x). Increased numbers of scattered small myeloblasts are highlighted by CD34 immunostain, accounting for 15% to 19% of the overall marrow cellularity.
Figure 3. Bone marrow biopsy at day 14 of first induction chemotherapy (H&E, 100x). The cellularity consists of dyspoietic megakaryocytes and erythroid precursors, in a background of chemotherapy-induced stromal damage.
Figure 4. Bone marrow biopsy at day 14 of first induction chemotherapy (CD34, 200x). Microphotograph of an area rich in small CD34-positive blasts.
Figure 5. Bone marrow biopsy at day 14 of second induction chemotherapy (H&E, 100x). The cellularity is comprised almost exclusively by abundant large atypical cells with frequent multinucleation, in a background of stromal damage.
Figure 6. Bone marrow biopsy at day 14 of second induction chemotherapy (H&E, 500x). Abundant large atypical cells with monolobated to polylobated nuclei, powdery chromatin, large prominent nucleoli and moderate amounts of amphophilic cytoplasm. Frequent Reed-Sternberg-like binucleated forms are observed.
Figure 7. Bone marrow biopsy at day 14 of second induction chemotherapy (H&E, 500x). High power field showing atypical mitotic figures (upper mid and upper right), in addition to multiple small cells with picnotic nuclei and hypereosinophilic cytoplasm.
Figure 8. Bone marrow biopsy at day 14 of second induction chemotherapy (CD34, 100x). CD34 highlights the endothelial cells and is negative on the large atypical cells.
Figure 9. Bone marrow biopsy at day 14 of second induction chemotherapy (CD45, 100x). CD45 highlights few scattered small lymphocytes and is negative on the large atypical cells.
Figure 10. Bone marrow biopsy at day 14 of second induction chemotherapy (Spectrin β1, 100x). Most of the bone marrow cellularity is strongly positive for spectrin β1.
Figure 11. Bone marrow biopsy at day 14 of second induction chemotherapy (Glycophorin A, 200x). Glycophorin A is variably positive on most nucleated cells.
Figure 12. Bone marrow biopsy at day 14 of second induction chemotherapy (Hemoglobin A, 200x). Variable weak staining for Hemoglobin A in a proportion of nucleated cells.
Additional figure 1: Summary