Diagnosis of chronic myelogenous leukemia in a dog using morphologic,cytochemical, and flow cytometric techniques

Abstract: Chronic myelogenous leukemia was diagnosed in a 3.5-year-old neutered male Golden Retriever. The diagnosis was based on persistent leukocytosis (>73.0×10³/μL), composed of a proportionate left shift to pro-granulocytes with no evidence of underlying inflammation, infection, or neoplasia. Marked dysplasia was evident in neutrophils and platelets in peripheral blood. Bone marrow and splenic aspirates were dominated by mature and immature neutrophils with < 2% myeloblasts. Cytochemical and flow cytometric assays confirmed that cells in the peripheral blood and spleen were of committed neutrophil lineage. The dog responded initially to treatment with hydroxyurea, but developed acute undifferentiated leukemia approximately 83 days after initial presentation.