Figure 1:

Microscopic pictures of myeloid neoplasms with STAT5B mutations (A-F) and bone marrow of a patient with peripheral T-cell lymphoma (PTCL)-NOS with STAT5B mutation (G-H). A: Marrow shows sheets of myeloblasts (Case #1, Bone marrow biopsy, HE x400), B: pSTAT5 immunohistochemistry shows immunoreactivity in myeloblasts (Case #1, Bone marrow biopsy, pSTAT5 ×400), C: Eosinophils and precursors are increased (Case #4, Bone marrow biopsy, HE x400), D: Peripheral blood shows increase in eosinophils (Case #4, Peripheral blood, Giemsa x500), E: Eosinophils and precursors are increased (Case #5, Bone marrow biopsy, HE x400), F: CD61 highlights numerous dysplastic megakaryocytes (Case #5, Bone marrow biopsy, CD61 ×200), G: Bone marrow shows increased eosinophils and precursors (PTCL-NOS, Bone marrow biopsy, HE x200), H: Peripheral blood shows increase in eosinophils (PTCL-NOS, Peripheral blood, Giemsa x500), I: Flow cytometry performed with bone marrow aspirate sample of PTCL-NOS patient shows small abnormal T-cell population with loss of surface CD3 (0.26% of total WBC), consistent with minimal bone marrow involvement by PTCL-NOS. J: Flow sorting was performed with a peripheral blood sample of Case #4 to isolate granulocytes, eosinophils, B-cells and T-cells to further perform NGS in each population, K: The results of subsequent next generation sequencing in each population of Case #4. STAT5B mutations were identified in granulocytes and eosinophils, but not in B-cells or T-cells.