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Melanoma

Canine melanoma is a malignant tumor made up of melanocytes, which are the cells that determine the dark pigmentation of the skin. When moles suddenly change shape and color, it can indicate a melanoma. Canine melanomas are typically located on the skin, toes or mouth. Melanomas in dogs don't have an established cause, unlike melanomas in people, which are typically caused by excessive exposure to ultraviolet irradiation. In fact, in dogs darkly pigmented skin is more susceptible to this type of cancer than light pigmented skin. Melanomas are common in dogs although not all are malignant.

Symptoms

  • Lesions that have a dark color or are irregular in shape
  • Refusal to eat
  • Moles that appear to itchy or bleed
  • Weight loss
  • Unusual lesions on the toes or in the mouth
  • Fatigue
  • Bad breath
  • Nausea
  • Excessive drooling, sneezing or coughing
  • Depression
  • Trouble swallowing
  • Behavioral changes

Breeds at Risk

  • Airedale Terriers
  • Giant and Miniature Schnauzers
  • Boston Terriers
  • Golden Retrievers
  • Boxer
  • Gordon Setters
  • Chihuahuas
  • Irish Setters
  • Chow Chows
  • Irish Terriers
  • Cocker Spaniels
  • Scottish Terriers
  • Doberman Pinschers
  • Springer Spaniels
  • Flat-coated Retrievers
 

Diagnosis

Melanomas in dogs can be diagnosed through a medical examination and biopsy. Additional diagnostic and staging evaluations may include complete blood count, serum biochemistry test, urinalysis, chest and abdominal radiographic views or ultrasound, biopsy with histopathological examination, fine-needle aspiration of lymph nodes or solid tumors or computed tomography scan.

Pet owners can play a critical role in early diagnosis of this cancer. It is very important to groom your dog on a regular basis so that you detect possible dermal melanomas as early as possible. More importantly, check inside the mouth for dark spots or lesions and look at the toes as well. Early detection and treatment of a melanoma can help prevent the cancer from spreading through the rest of the body.

Treatment

Treatment for canine melanoma focuses on removing the melanoma and preventing the cancer from spreading. The veterinarian will establish if surgery is possible or recommended. If surgery is not possible, chemotherapy and radiation therapy are other options. A dog with melanoma can live a quality life, provided there is an early diagnosis and the dog gets the necessary care and treatment.

Prognosis

Melanomas around the eyelid and on the skin are often benign and don’t often spread. Those that occur in the nail bed are usually locally invasive and may spread along the lymphatic vessels to the closest lymph node. Oral melanomas are aggressive and invasive and can spread quickly.

Melanomas in the oral cavity have a poor prognosis if they are large (>2 cm diameter). Even with surgery or treatment, the cancer can reoccur or spread. Tumors spread quickly when they are not treated, and they may spread even if treatment is tried. Even though the prognosis for oral melanoma is not very good, treatment may prolong the dog’s life.

Current Research

Click here to find out about Morris Animal Foundation--funded research into melanoma.

Disclaimer
Morris Animal Foundation urges pet owners not to implement any suggestions on animal health treatments without prior consultation with their licensed veterinarian. If your pet is experiencing health issues, contact your licensed veterinarian. The Foundation funds research to enhance medical options available to veterinary professionals and their patients.