Variable appearance of myeloid leukemia in mice.

(A) MPD-like myeloid leukemia. Note complete maturation of myeloid forms to segmented neutrophils (Wright Giemsa, × 1000). Myeloproliferative disease can exhibit a similar morphology but lacks the constellation of other features that characterize leukemias. (B) Myeloid leukemia with maturation showing macrophages dispersed among the tumor cells (hematoxylin and eosin [H&E], × 100). (C) Myeloid leukemia with maturation. Note heterogeneous differentiation and large macrophages with striated eosinophilic cytoplasm (H&E, × 400). (D) Myeloid leukemia with maturation with many ring forms (H&E, × 1000). (E) Myeloid leukemia without maturation. Note many immature forms/blasts with azurophilic granules (Wright Giemsa, × 1000). (F) Myeloid leukemia without maturation seen as a poorly differentiated tumor in the splenic red pulp. No evidence of myeloid maturation can be seen. Residual nucleated erythroid cells are present (H&E, × 400).