Myeloperoxidase-positive acute megakaryoblastic leukemia in a dog

H.M.T. Ferreira, Sionagh Smith, A.M. Schwartz, Elspeth Milne

Research output: Contribution to journalArticlepeer-review


A 16-month-old female spayed Labrador Retriever was referred to the University of Edinburgh for exercise intolerance, inappetence, and severe anemia. A CBC showed severe nonregenerative anemia and moderate numbers of atypical cells with morphologic features most consistent with megakaryoblastic origin. Similar cells were identified in a bone marrow aspirate and accounted for 23% of all nucleated cells. Atypical promegakaryocytes and megakaryocytes were also noted. Myelodysplastic syndrome affecting the megakaryocytic lineage was suspected. Cytologic examination of a fine-needle aspirate of the spleen revealed rare megakaryoblasts similar to those in blood and bone marrow. At necropsy, the bone marrow consisted of atypical megakaryoblasts and megakaryocytes that were also infiltrating spleen, liver, lymph nodes, renal perihilar tissue, and visceral adipose tissue, consistent with acute megakaryoblastic leukemia. Immunohistochemical analysis of splenic sections confirmed megakaryoblastic origin (immunoreactive for CD61 and von Willebrand factor). Some leukemic cells were also immunoreactive for myeloperoxidase (MPO). This aberrant immunophenotype suggested both megakaryocytic and granulocytic/monocytic differentiation of the leukemic cells. To our knowledge, this is the first report of MPO-positive acute megakaryoblastic leukemia in a dog.
Original languageUndefined/Unknown
Pages (from-to)530-537
Number of pages8
JournalVeterinary Clinical Pathology: An International Journal of Laboratory Medicine
Issue number4
Publication statusPublished - 2011


  • Acute myeloid leukemia dysmegakaryocytopoiesis megakaryocyte myelodysplastic syndromes spleen growth-factor-beta platelet dysfunction myeloid neoplasms classification myelofibrosis radiation cells

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