A Primer On Melanomas in Dogs

Malignant melanomas are common in the mouth and on the skin and digits of the feet.  

Tumors may form on haired or hairless skin, and they may appear pigmented or non-pigmented. The tumors may grow rapidly, ulcerate, or bleed.

A Primer On Melanomas in Dogs

What does it look like

Oral melanoma

Oral melanomas represent about 80% of melanomas diagnosed in dogs. Age and breed increase the risk–older dogs, especially small breeds, are most susceptible. Most vulnerable breeds include:

  • Miniature Poodles
  • Cocker Spaniels
  • Chows
  • Golden Retrievers

Oral melanomas usually develop as solitary tumors but are quite invasive. They are typically black but not always. While usually, oral melanoma is a distinct mass, some might be more of a flat plaque lesion.

Other signs of malignant melanomas in dogs’ mouths include:

  • lack of appetite
  • bad breath
  • or difficulty eating

Malignant melanomas can spread, or metastasize, to almost any area of the dog’s body, and other clinical signs depend on the affected area. For example, metastatic melanoma in the lungs may cause trouble breathing.

Other types

Other locations that can develop melanoma include:

  • nailbeds
  • skin
  • eyes

Melanoma diagnosis

Your veterinarian will diagnose melanoma by examining a sample of cells they collect from the lesion or lump. However, fine needle aspirate is not always enough, and your dog might require a biopsy.

Staging of the tumor helps determine how aggressive the cancer is and might involve:

  • bloodwork
  • local lymph node aspirate
  • x-rays
  • ultrasound

Dog melanoma treatment


The primary treatment for melanoma in dogs is the surgical removal of the lump. Melanomas on a dog’s digit usually require amputation of the toe.

Chemotherapy, radiation therapy, or immunotherapy may be recommended.


Radiation is effective for melanomas that, due to their location or size, cannot be removed. It also helps prevent regrowth when the surgeon cannot remove the tumor completely.

Melanoma vaccine

Local treatment such as surgery or radiation addresses the tumor but doesn’t address potential metastasis. Melanoma vaccine is the current treatment to delay recurrence and metastasis. The vaccine helps the dog’s immune system recognize and fight the cancer.

Related articles:
Bad Odor in Dogs: Why Is My Dog Stinky?

Further reading:
Melanoma: Location, Location, Location
Malignant Melanoma in Dogs – A Colorful Canine Cancer

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