1. Acute monocytic leukemia in Erdheim Chester Disease patient
Barina Aqil, MD and Friederike Kreisel, MD
Case#: W & W

2. Lung Wedge Biopsy W

3. Figure 1. Lung wedge biopsy with dense bands of mixed inflammatory infiltrates (H&E, 20X)

4. Figure 2. Lung wedge biopsy with plasma cells, lymphocytes, histiocyte-like cells and eosinophils (H&E, 100X)

5. Histiocyte-like cell
Figure 3. Lung wedge biopsy with mononuclear cells with oval nuclei, small prominent nucleoli and moderate amounts of cytoplasm (H&E, 400X)

6. Figure 4
Factor XIII
Factor XIII
S100
CD68

7. Figure 5. BRAF V600E

8. Bone marrow biopsy W

9. Figure 6. Peripheral blood with circulating blasts (Giemsa, 1000X)

10. Figure 7. Bone marrow aspirate with increased blasts (medium to large, with high nuclear to cytoplasmic ratio, moderate amount of basophilic cytoplasm and vacuolation )(Giemsa, 1000X)

11. Figure 8. Hypercellular core biopsy with sheets of mononuclear cells (H&E, 400X)

12. Figure 9
Myeloperoxidase
CD33
Lysozyme
CD68

13. Figure 10. BRAF V600E