Felis ISSN 2398-2950


Synonym(s): Malignant lymphoma, Lymphosarcoma, LSA

Contributor(s): William Brewer Jr, Laura Garrett, Irene Rochlitz


  • Cats have a higher incidence of lymphoma than dogs (20-30% of all tumors in cats).
  • Lymphoid neoplasia accounts for an incidence of 200 per 100,000 cats at risk and is 90% of all feline hemopoietic neoplasms.
  • Lymphoma can originate in any organ or tissue containing lymphocytes:
  • Cause: some forms associated with FeLV infection (only 25% of cases in a recent report which represents a decrease over previous years).
  • Signs: depend on form, eg malaise, weight loss, respiratory distress, vomiting, diarrhea.
  • Diagnosis: cytology, histopathology.
  • Treatment: cytotoxic drugs, surgery if alimentary and obstructed; radiation therapy for nasal, rapid reduction of large problematic masses such as mediastinal form and consolidation therapy following chemotherapy, surgery for ocular.
  • Prognosis: Poor if no treatment.
    Print off the owner factsheet Feline lymphoma Feline lymphoma to give to your client.




  • FeLV Feline leukemia virus disease for some forms (not alimentary)
    • Mediastinal 80% FeLV positive.
    • Alimentary <30% FeLV positive.
    • Multicentric 80% FeLV positive.
    • CNS 80% FeLV positive.
    • Cutaneous <10% FeLV positive.
    • Renal 50% FeLV positive.
    • Often occurs in households of FeLV infected cats.


  • Relative incidence of different forms varies with geographical region (and therefore depends on study):
    • Alimentary: 30-50% Scotland (but 15% in New York).
    • Mediastinal: 25-38% England (but 18% Scotland).
    • Multicentric: 20-44%.
    • Renal Kidney: neoplasia.
    • Spinal: rare (but most common spinal neoplasm in cat).
  • Malignant proliferation of lymphoid cells arising in any area containing lymphoid tissue   →   focal or diffuse masses in intestine, skin, thymus or lymph nodes   →   progresses to extranodal sites, eg liver, spleen, bone marrow.
  • Stage 1Neoplasia: TNM staging:
    • Single tumor.
  • Stage 2:
    • Single tumor and regional lymph node involvement.
    • Two single tumors on same side of diaphragm.
    • Resectable gastrointestinal lesion.
  • Stage 3:
    • Two single tumors on opposite sides of diaphragm.
    • Inoperable intra-abdominal mass.
    • Spinal neoplasia.
  • Stage 4:
    • Stage 1-3 plus liver/spleen involvement.
  • Stage 5:
    • Stage 2-4 plus CNS or bone marrow involvement (leukemic).


  • Rapidly fatal (6-8 weeks) without treatment in most cases.
  • Months (nasal, cutaneous forms).


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Williams L E, Pruitt A F, Thrall D E (2010) Chemotherapy followed by abdominal cavity irradiation for feline lymphoblastic lymphoma. Vet Radiol Ultrasound 51 (6), 681-687 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
  • Brown M R, Rogers K S, Mansell K J et al (2003) Primary intratracheal lymphosarcoma in four cats. J Am Anim Hosp Assoc 39 (5), 468-472 PubMed.
  • Teske E, van Straten G, van Noort R et al (2002) Chemotherapy with cyclophosphamide, vincristine, and prednisolone (COP) in cats with malignant lymphoma: new results with an old protocol. JVIM 16 (2), 179-186 PubMed
  • Kristal O, Lana S E, Ogilvie G K et al (2000) Single agent chemotherapy with doxorubicin for feline lymphoma - a retrospective study of 19 cases (1994-1997). JVIM 15 (2), 125-130 PubMed.
  • Parnell N K, Powell L L, Hohenhaus A E et al (1999) Hypoadrenocorticism as the primary manifestation of lymphoma in two cats. JAVMA 214 (8), 1208-1211, 1200 PubMed.
  • Gabor L J, Malik R, Canfield P J (1998) Clinical and anatomical features of lymphosarcoma in 118 cats. Aust Vet J 76 (11), 725-732 PubMed.
  • Court E A, Watson A D & Peaston A E (1997) Retrospective study of 60 cases of feline lymphosarcoma. Aust Vet J 75 (6), 424-427 PubMed.
  • Meleo K A (1997) The role of radiotherapy in the treatment of lymphoma and thymoma. Vet Clinics NA SAP 27 (1), 115-129 PubMed.
  • Moore A S, Cotter S M, Frimberger A E et al (1996) A comparison of doxorubicin and COP for maintenance of remisssion in cats with lymphoma. JVIM 10 (6), 372-375 PubMed.
  • Mahony D M, Moore A S, Cotter S M et al (1995) Alimentary lymphoma in cats 28 cases (1988-1993). JAVMA 207 (12), 1593-1598 PubMed.
  • Mooney S C, Hayes A A, McEwan E G et al (1989) Treatment and prognostic factors in lymphoma in cats 103 cases (1977-1981). JAVMA 194 (5), 696-702 PubMed.
  • Mooney S C, Hayes A A, Matus R E et al (1987) Renal lymphoma in cats 28 cases (1977-1984). JAVMA 191 (11), 1473-1477 PubMed.