Canis ISSN: 2398-2942

Leukemia

Synonym(s): Myeloproliferative, Lymphoproliferative

Contributor(s): Ruthanne Chun

Introduction

  • The presence of excessive numbers of abnormal, neoplastic cells in bone marrow +/- peripheral blood.
  • Bothmyeloproliferativeandlymphoproliferativediseases, classified as acute versus chronic and by cell lines affected (see below).
  • Signs: non-specific, due to consequences of disease process, eg cytopenia, hypercalcemia.
  • Diagnosis: peripheral blood smears, bone marrow aspirate/biopsy.
  • Treatment: supportive, symptomatic, specific cytotoxic agents depending on type of leukemia.
  • Prognosis: favorable chronic, grave for acute leukemias.

Pathogenesis

Etiology

  • Unknown.
  • Endogenous retroviral sequences have been demonstrated in the canine genome but the significance of these is unknown.
  • Genetic factors, environmental factors, radiation and chemical exposure should be considered.

Pathophysiology

  • Neoplastic transformation of cells involved in hematopoiesis → massive proliferation of neoplastic cells.
  • Transformation of stem cells or early precursors → proliferation of immature cells incapable of maturation →acute leukemia→ large numbers of immature cells in bone marrow and peripheral blood → severe non-regenerative cytopenia → may result in bleeding (thrombocytopenia), sepsis (neutropenia), profound weakness and lethargy (anemia).
  • Disseminated intravascular coagulation → bleeding diasthesis.
  • Transformation of late precursor cells → proliferation of mature, differentiated cells →chronic leukemia→ less severe cytopenia.
  • Excessive numbers of circulating cells or, rarely, hyperproteinemia → hyperviscosity → decreased oxygen transport to capillary beds → microthrombi of tumor cells.
  • Production of humoral factors, eg PTH-rp or parathyroid related peptide, → stimulation of osteoclasts → hypercalcemia of malignancy → polyuria/polydypsia → renal failure.

Timecourse

  • Acute leukemia progresses rapidly over days/weeks.
  • Chronic leukemia over months/years.

Diagnosis

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Treatment

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Dobson J, Villiers E & Morris J (2006) Diagnosis and management of leukaemia in dogs and cats. In Practice 28 (1), 22-31 VetMedResource.
  • Modiano J, Smith R et al (1998) The use of cytochemistry, immunophenotyping, flow cytometry, and in vitro differentiation to determine the ontogeny of a canine monoblastic leukemia. Vet Clin Pathol 27 (2), 40-49 PubMed.
  • Grindem C B (1996) Blood cell markers. Vet Clin North Am Small Anim Pract 26 (5), 1043-1064 PubMed.


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