Acute leukemia and precursor neoplasms. (A) Precursor B-lymphoblastic leukemia with a very high WBC with numerous blasts and smudge cells. (B) Precursor B-lymphoblastic leukemia with 2 large lymphoblasts. (C) Precursor T-lymphoblastic leukemia with a lymphoblast containing a moderate amount of basophilic cytoplasm. (D) APL with t(15;17)(q22;q12); PML-RARA, the hypogranular variant with butterfly-shaped nuclei. (E) APL with an abnormal promyelocyte containing multiple Auer rods below a lymphocyte. (F) Transient abnormal myelopoiesis associated with Down syndrome in an infant with numerous large blasts, hypogranular platelets, nucleated RBCs, a megakaryocytic nuclear fragment, and scattered schistocytes. (G) Acute monoblastic leukemia with abundant lightly granular cytoplasm containing vacuoles. (H) Acute myeloid leukemia with t(8;21)(q22;q22); RUNX1-RUNX1T1 with a small myeloblast containing a thin, delicate Auer rod. (I) Recurrent acute myeloid leukemia with associated microangiopathic hemolysis (schistocytes) and a hypogranular platelet. The 2 myeloblasts at bottom right contain partially condensed chromatin and sparsely granular cytoplasm, features sometimes found in blasts seen in myeloid neoplasms with myelodysplasia.