Felis ISSN 2398-2950


Synonym(s): Mast cell tumor

Contributor(s): William Brewer Jr, Susan North, David Scarff, Suzanne Murphy


  • Less common than dog but approximately 15% of all feline tumors.
  • Cutaneous and visceral forms - splenic, intestinal.
  • Diagnosis: cytology, histopathology.
  • Treatment: surgical excision, radiotherapy, chemotherapy.
  • Prognosis: cutaneous: good; visceral: guarded.


Predisposing factors


  • Breed - Siamese Siamese for cutaneous form.



  • Most cutaneous tumors localized (mastocytic) or regress (atypical).
  • Occasionally (up to 22% mastocytic) spread to lymph nodes and or internal organs.
  • Multiple cutaneous tumors, may have appearance of miliary dermatitis Dermatitis: miliary  (rare).
  • Atypical: spontaneous regression over 4-24 months.


  • Widespread metastasis common to liver and spleen, local lymph nodes, leading to hepato-splenomegaly, depression, anorexia, vomiting, diarrhea, weight loss, intestinal obstruction, peritoneal effusion.
  • Peripheral mastocytosis/anemia relatively common with splenic form.
  • Coagulopathies common with splenic tumors.
  • Splenomegaly may be present for a long time before clinical disease seen.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Barrett L E, Skorupski K, Brown D C, Weinstein N, Clifford C, Szivek A, Haney S, Kraiza S, Krick E L (2018) Outcome following treatment of feline gastrointestinal mast cell tumours. Vet Comp Oncol 16(2), 188-193 PubMed.
  • Berger E P, Johannes C M, Post G S, Rothchild G, Shiu K B, Wetzel S, Fox L E (2018) Retrospective evaluation of toceranib phosphate (Palladia) use in cats with mast cell neoplasia. J Feline Med Surg 20(2), 95-102 PubMed.
  • Sabattini S, Barzon G, Giantin M, Lopparelli R M, Dacasto M, Prata D, Bettini G (2017) Kit receptor tyrosine kinase dysregulations in feline splenic mast cell tumours. Vet Comp Oncol 15(3), 1051-1061 PubMed.
  • Kraus K A, Clifford C A, Davis G J, Kiefer K M, Drobatz K J (2015) Outcome and Prognostic Indicators in Cats Undergoing Splenectomy for Splenic Mast Cell Tumors. J Am Anim Hosp Assoc 51(4), 231-238 PubMed.
  • Henry C, Herrera C (2013) Mast cell tumors in cats: clinical update and possible new treatment avenues. J Feline Med Surg 15(1), 41-47 PubMed.
  • Piviani M, Walton R M, Patel R T (2013) Significance of mastocytemia in cats. Vet Clin Pathol 42(1), 4-10 PubMed.
  • Rassnick K M, Williams L E, Kristal O et al (2008) Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005). JAVMA 232 (8), 1200-1205 PubMed.
  • Litster A L, Sorenmo K U ( 2006) Characterisation of the signalment, clinical and survival characteristics of 41 cats with mast cell neoplasia. J Feline Med Surg 8(3), 177-183 PubMed.
  • Turrel J M, Farrelly J, Page R L et al (2006) Evaluation of strontium 90 irradiation in treatment of cutaneous mast cell tumors in cats: 35 cases (1992-2002). JAVMA 228 (6), 898-901 PubMed.
  • Wilcock B P, Yager J A & Zink M C (1986) The morphology and behavior of feline cutaneous mastocytomas. Vet Pathol 23 (3), 320-324 PubMed.

Other sources of information

  • London C A & Thamm D H (2012) Mast cell tumors. In: Withrow S J, Vail D M & Page R L (eds). Withrow and MacEwen’s Small Animal Clinical Oncology. 5th edn. St Louis:Elsevier. pp 335-355.