Felis ISSN 2398-2950

Acute lymphoblastic leukemia

Synonym(s): ALL, Lymphoproliferative disease

Contributor(s): Laura Garrett, Jo Morris


  • Cause: acute onset of progressive, malignant infiltration of bone marrow and lymphatic organs by immature, poorly differentiated lymphoblasts which are commonly present in blood. Most cases are FeLV positive.
  • Signs: non-specific but often severe, eg anorexia, weakness, vomiting, diarrhea, pyrexia and occasionally neurological signs.
  • Diagnosis: numerous lymphoblasts in bone marrow and similar cells in peripheral circulation.
  • Treatment: supportive and cytotoxic agents may be tried.
  • Prognosis: poor due to severe cytopenias.




  • Normal hemopoietic cells are crowded out of bone marrow by neoplastic lymphoblasts which proliferate rapidly.
  • Results in neutropenia, thrombocytopenia and anemia.
  • Neoplastic lymphoblasts may also spill out into the peripheral blood   →   leukocytosis.
  • FeLV Feline leukemia virus disease most common cause.
  • FIV infection Feline immunodeficiency virus disease may also predispose.
  • Neoplastic transformation of lymphoid precursor cells   →   proliferation of early lymphoid cells   →   crowds out bone marrow, competes for nutrients, release of inhibitory substances   →   reduced production of normal hemopoietic cells   →   profound cytopenias.
  • Neutropenia   →   infections, sepsis.
  • Thrombocytopenia Thrombocytopenia   →   spontaneous bleeding, petechial hemorrhages, intestinal bleeding.
  • Non-regenerative anemia Anemia: overview  →   weakness, fatigue.
  • Neoplastic lymphoblasts often infiltration of lymphatic tissue   →   splenomegaly, hepatomegaly   →   organ dysfunction; and sometimes lymphadenopathy which is mild compared with lymphadenopathy due to lymphoma.
  • Occasionally central nervous system (CNS) is infiltrated   →   neurological signs, eg seizures  Seizures.


  • Rapid - weeks.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Roccabianca P, Vernau W, Caniatti M et al (2006) Feline large granular lymphocyte (LGL) lymphoma with secondary leukemia: primary intestinal origin with predominance of a CD3/CD8(alpha)(alpha) phenotype. Vet Pathol 43 (1), 15-28 PubMed.
  • Louwerens M, London C A, Pedersen N C et al (2005) Feline lymphoma in the post-feline leukemia virus era. J Vet Intern Med 19 (3), 329-335 PubMed.
  • Stockham S L, Keeton K S, Szladovits B (2003) Clinical assessment of leukocytosis: distinguishing leukocytoses caused by inflammatory, glucocorticoid, physiologic, and leukemic disorders or conditions. Vet Clin North Am Small Anim Pract 33 (6), 1335-1357 PubMed.
  • Shelton G H, McKim K D, Cooley P L et al (1989) Feline leukemia virus and feline immunodeficiency virus infections in a cat with lymphoma. J Am Vet Med Assoc 194 (2), 249-252 PubMed.
  • Cotter S M (1983) Treatment of lymphoma and leukemia with cyclophosphamide, vincristine and prednisone: II Treatment of cats. J Am Anim Hosp Assoc 19 (2), 166-172 VetMedResource.