Felis ISSN 2398-2950


Synonym(s): Malignant melanoma

Contributor(s): Philip K Nicholls, Marion O'Leary, Laura Garrett, Susan North, Isabelle Desmas-Bazelle


  • Less common in the cat than in the dog and horse, but not rare, comprising <2% of feline tumors, and 0.5% of feline skin tumors.
  • Eye and skin affected more often than oral cavity.
  • Diagnosis: cytology, histopathology.
  • Treatment: surgical resection +/- radiotherapy & chemotherapy +/- immunotherapy.
  • Prognosis: 29-47% of melanocytic feline skin tumors are benign. Recurrence and metastasis are common in malignant melanoma.
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  • Occur experimentally with feline sarcoma virus (FeSV) Feline sarcoma virus infection.
  • Unlikely to be cause of naturally occurring melanomas.


  • Neuroecrodermal origin.
  • Melanin is transferred to keratinocytes.
  • Benign tumors - local problem only.
  • Malignant tumors - metastasis to distant sites (lung and liver common), usually via lymph nodes.


  • Primary mass may not cause a problem unless very large.


  • Primary mass may obscure vision or cause secondary glaucoma, uveitis.
  • Eyelid and ocular surface - majority malignant.
  • Limbic (scleral/subconjunctival) - majority benign.
  • Intra-ocular - majority malignant but slow time course for both primary lesion and metastasis.
  • Feline conjunctival lymphoma - majority malignant.


  • Benign tumors slow growing.
  • Malignant tumors often slow to metastasize - several years for ocular lesions.
  • Malignant cutaneous melanomas very aggressive and metastasize rapidly (rare).


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Sarbu L, Kitchell B E, Bergman P J (2017) Safety of administering the canine melanoma DNA vaccine (Oncept) to cats with malignant melanoma - a retrospective study. J Feline Med Surg 19 (2), 224-230 PubMed.
  • Wiggans K T, Reilly C M, Kass P H et al (2016) Histologic and immunohistochemical predictors of clinical behavior for feline diffuse iris melanoma. Vet Ophthalmol 19 (Suppl 1), 44-55 PubMed.
  • Schobert C S, Labelle P, Dubielzig R R (2010) Feline conjunctival melanoma: histopathological characteristics and clinical outcomes. Vet Ophthalmol 13 (1), 43-46 PubMed.
  • Farrelly J, Denman D L, Hohenhaus A E et al (2004) Hypofractionated radiation therapy of oral melanoma in five cats. Vet Radiol Ultrasound 45 (1), 91-93 PubMed.
  • Ramos-Vara J A, Miller M A, Johnson G C et al (2002) Melan A and S100 protein immunohistochemistry in feline melanomas: 48 casesVet Pathol 39 (1), 127-132 PubMed.
  • Smith S H, Goldschmidt M H, & McManus P M (2002) A comparative review of melanocytic neoplasms. Vet Pathol 39 (6), 651-678 PubMed.
  • Luna L D, Higginbotham, Henry C J et al (2000) Feline non-ocular melanoma- a retrospective study of 23 cases (1991-1999). J Fel Med Surg (4), 173-181 PubMed.
  • Betton A, Healy L N, English R V et al (1999) Atypical limbal melanoma in a cat. JVIM 13 (4), 379-381 PubMed.
  • Roels S, Tilmant K & Ducatelle R (1999) PCNA and Ki67 proliferation markers as criteria for prediction of clinical behavior of melanocytic tumors in cats and dogs. J Comp Pathol 121 (1), 13-24 PubMed.
  • van der Linde-Sipman J S, de Wit M M, van Garderen E et al (1997) Cutaneous malignant melanomas in 57 cats: identification of (amelanotic) signet-ring and balloon cell types and verification of their origin by immunohistochemistry, electron microscopy, and in situ hybridization. Vet Pathol 34 (1), 31-38 PubMed.
  • Day M J & Lucke V M (1995) Melanocytic neoplasia in the cat. JSAP 36 (5), 207-213 PubMed.
  • Miller W H Jr., Scott D W & Anderson W I (1993) Feline cutaneous melanocytic neoplasms: a retrospective analysis of 43 cases (1979-1991). Vet Dermatol (1), 19-26 VetMedResource.

Other sources of information

  • Vail D M, Withrow S J, Page R L (2013) Melanoma. In: Small Animal Clinical Oncology. Eds S J Withrow & E G MacEwen. 5th edn. Philadelphia: W B Saunders Co. pp 321-334.
  • Miller P E & Dubielzig R (1996) Ocular tumors. In: Small Animal Clinical Oncology. Eds S J Withrow & E G MacEwen. 2nd edn. Philadelphia: W B Saunders Co. pp 421-431.
  • Carpenter J L, Andrews L K & Holzworth J (1987) Tumors of the melanogenic system. In: Diseases of the Cat, Medicine and Surgery. Ed J Holzworth. Philadelphia: W B Saunders Co. pp 579-583.