A retrospective study of the incidence and classification of bone marrow disorder in cats (1996–2004)

Abstract

An 8-year retrospective study of bone marrow reports was conducted to evaluate the incidence and classification of feline bone marrow disorders. Bone marrow reports from 203 cats were reviewed. Blood smears, bone marrow aspiration smears, bone marrow core biopsy specimens, and case records were reviewed for all cats with the exception of those bone marrows reported to be nondiagnostic or cytologically normal. Bone marrows with nonneoplastic/nonmyelodysplastic pathologic changes (n=96) were subclassified into 16 categories. Frequently observed disorders included erythroid hyperplasia, nonregenerative immune-mediated anemia, pure red cell aplasia, aplastic anemia, bone marrow necrosis, myelofibrosis, and lymphocytosis. Dysmyelopoiesis (n=27) was subcategorized into myelodysplastic syndromes (n=20) and secondary (n=7) dysmyelopoiesis. Thirty-four cases of acute leukemia, 3 cases of chronic lymphocytic leukemia, and 14 cases of other neoplasia were identified. These results indicate that a relatively small group of disorders account for the majority of the feline bone marrow disorders. Routine evaluation of blood and bone marrow aspiration smears and core biopsy specimens is needed for proper classification of bone marrow disorders. Ancillary testing, including flow cytometry and immunophenotyping, are useful in some circumstances.