Evaluation of dysmyelopoiesis in cats: 34 cases (1996-2005)

OBJECTIVE: To further classify dysmyelopoiesis as diagnosed by use of a general classification scheme and to determine clinical features and laboratory test results that could be used to differentiate between the various forms of dysmyelopoiesis in cats. DESIGN: Retrospective case series. Sample Population-Bone marrow slides from 34 cats. PROCEDURES: Medical records of cats in which dysmyelopoiesis was diagnosed on the basis of blood and bone marrow analyses from 1996 to 2005 were reviewed. Criteria for inclusion in the study were findings of > 10% dysplastic cells in 1 or more hematologic cell lines in the bone marrow and concurrent cytopenias in the blood. Cats that met these criteria were classified into subcategories of myelodysplastic syndromes or secondary dysmyelopoiesis on the basis of reevaluation of slides. RESULTS: Of 189 bone marrow slides reviewed, 34 (14.9%) had > 10% dysplastic cells in 1 or more cell lines. Cats were subcategorized as having myelodysplastic syndrome with excessive numbers of blast cells (n = 13), myelodysplastic syndrome with refractory cytopenias (8), a variant form of myelodysplastic syndrome (1), and secondary dysmyelopoiesis (12). Findings of dysmyelopoiesis and autoagglutination in cats with myelodysplastic syndrome and in those with immune-mediated anemia complicated differentiating between the 2 conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Differentiating cats with myelodysplastic syndromes from cats with immune-mediated hemolytic anemia was difficult because severe anemia and autoagglutination may be concurrent findings in both conditions. Differentiating between myelodysplastic syndrome with excessive numbers of blast cells and myelodysplastic syndrome with refractory cytopenias was useful in predicting clinical outcome.