Keynote Message
Bone marrow (BM) aspiration cytology is a cost-effective diagnostic tool, which provides excellent morphological detail of cells and infectious agents. The major indications for BM aspiration include unexplained clinical manifestations (e.g., fever, lameness), persistent hematological or biochemical abnormalities (e.g., non-regenerative anemia, persistent neutropenia or extreme leucocytosis, pancytopenia, hyperglobulinemia), diagnosis and/or staging of malignancies (e.g., lymphoma, mast-cell tumor), diagnosis of infectious diseases such as leishmaniosis and canine monocytic ehrlichiosis (CME), and evaluation of canine iron stores. It is very important to correlate BM findings with a complete blood count taken at or very near the time of BM sampling. A systematic approach to examination should be adopted, evaluating one cell series at a time, checking for orderly maturation and for any morphological abnormalities which could suggest dysplasia. A 500-cell differential count is ideal, although sometimes 200 or 300 are counted. Intra-marrow causes of isolated non-regenerative anaemia include non-regenerative immune-mediated hemolytic anemia (NRIMHA), pure red cell aplasia, erythroid hypoplasia, myelofibrosis, and myelodysplasia (subtype refractory anemia). Isolated neutropenia may be due to increased consumption at a focus of inflammation, margination or reduced production. The latter can result from immune-mediated neutropenia in which the target may be the neutrophil, or less commonly, an earlier neutrophil precursor. Bi- or pancytopenias may result from aplastic anemia (myelosuppressive CME, feline and canine parvoviral infections, feline leukemia virus infection, idiopathic), BM necrosis, myelophthisic syndromes (acute leukemias, myeloproliferative neoplasms, stage V lymphoma, metastatic neoplasms, severe granulomatous inflammation in histoplasmosis), myelodysplastic syndromes, and rarely myelofibrosis and NRIMHA. In this session, selected neoplastic and non-neoplastic BM diseases will be addressed and illustrated with case examples.
Key References
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3. Devine L, Armstrong PJ, Whittemore JC, et al. Presumed primary immune-mediated neutropenia in 35 dogs: a retrospective study. Journal of Small Animal Practice. 2017;58(6):307–313. DOI: 10.1111/jsap.12636.
4. Stacy NI, Harvey JW. Bone marrow aspirate evaluation. Veterinary Clinics of North America: Small Animal Practice. 2017;47:31–52. DOI: 10.1016/j.cvsm.2016.07.003.
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