Some breeds of dogs, particularly those that are black or have a dark coat, are prone to melanoma, which is a form of cancer of the skin. Malignant melanoma is caused by a tumor in the melanocytes that are the cells in the skin that produce pigment or coloration. Small bumps will appear in the mouth, on the skin or between the toes and are often very fast growing. They may be black or dark brown in color and will typically have irregular, rough edges. Sometimes the tumor may stay quite small and then suddenly start to grow. The biggest concern with malignant melanoma is that the cancer quickly spreads to other organs of the body, often with fatal results. Typically the diagnosis of malignant melanoma is between the ages of 9-12 and is most common in dark colored male dogs.
While there is no known cause of melanoma it is believed to be genetically linked as it tends to occur most commonly within specific breeds and specific breeding lines within the breed. The most common breeds associated with melanoma on the skin and toes include Flat Coated Retrievers, Boston Terriers, Scottish Terriers, Airedales, Boxers, Irish Setters, Irish Terriers, Dobermans, Chow Chows and Chihuahuas. In addition Poodles are often diagnosed with melanomas in the mouth as are the Dachshund, Scottish Terriers and Golden Retrievers. The Schnauzer breeds and the Gordon Setter are occasionally seen with either the oral, skin or toe types of malignant melanoma.
The first signs of the skin or toe variety of melanoma are the irregularly pigmented bumps on the skin. Usually these bumps do not seem to bother the dog, although if they are scratched they can become infected, leading to further problems. Tumors in the skin of the mouth results in swelling, drooling, bleeding from the area and a very bad odor in the mouth. Often eating becomes difficult and the dogs may even have trouble breathing if the tumors have spread through the respiratory system. The melanomas on the toes are bumps between the pads of the feet that can cause irritation and lameness.
If the tumor can be surgically removed most vets recommend this treatment option. In cases where the melanoma is on the toes amputation of the toe or toes may be required to remove all the tissue. Surgical removal of the tumors in the mouth may require removal of part of the gum or jaw. If the tumor is too large or inoperable, chemotherapy treatments are another option. A new treatment option, Canine Melanoma Vaccine DNA, can be given to dogs with stage I or stage ll oral melanomas.
In addition immunotherapy is required for the dog to help them stay healthy through the treatment process. The vet will need to carefully and routinely examine the dog for any signs of malignant growths in any other body organs and owners need to continually be monitoring the dog for any other signs of growths. Up to half of all skin types of melanomas are malignant, so early treatment and aggressive treatment is the only way to help protect the dog from developing other tumors.