Acute monocytic leukemia in Erdheim Chester Disease patient Barina Aqil, MD and Friederike Kreisel, MD Case#: W15-3056 & W15-6309

Lung Wedge Biopsy W15- 3056

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

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

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)

Figure 4 Factor XIII Factor XIII S100 CD68

Figure 5. BRAF V600E

Bone marrow biopsy W15-6309

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

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)

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

Figure 9 Myeloperoxidase CD33 Lysozyme CD68

Figure 10. BRAF V600E