What is melanoma in dogs?
Melanoma is a cancer that happens in dogs as a result of the unregulated proliferation of melanocytes, a cell that resides in the skin and mucus membranes of mammals. Older dogs are especially prone to this cancer, particularly to its highly aggressive oral form. In fact, melanoma of the mouth accounts for almost 40% of all oral tumors seen in dogs.
If you find something suspicious on your dog, it's always best to err on the side of caution and take your dog to the vet for a full examination as soon as possible.
What are the symptoms of melanoma in dogs?
Melanoma in dogs typically presents as a dark, pigmented mass on the skin or in the mouth. Other symptoms may include changes in the size, shape, or color of existing moles, ulcers that do not heal, and swelling in the affected area. You can find pictures of what melanoma looks like in dogs by using your favorite search engine. This can help you determine if the mass on your dog is a cause for concern.
Certain dog breeds are more susceptible to melanoma, including Scottish Terriers, Chow Chows, and Golden Retrievers. These breeds have a higher risk due to genetic predisposition and exposure to sunlight. Regular veterinary check-ups and sun protection can help reduce the risk of melanoma in these breeds.
What types of melanoma can dogs get?
There are 4 types of melanoma that have been found in dogs.
Oral Melanoma
On average, 80% of melanomas we see in dogs will be in the dogs mouth. They are typically seen in dogs ages 10 years and older, and small breeds are at higher risk of developing melanoma. Miniature poodles, cocker spaniels, chows and golden retrievers are the most likely breeds to be affected, although any breed can be diagnosed with melanoma.
These tumors can be quite invasive, extending into underlying soft tissue and bone. Although many oral melanomas will exhibit dark pigmentation and appear black in color, this is not always the case. Some tumors may be pink or exhibit mixed coloring. Additionally, not all melanomas will present as a distinct mass. Some will present as more of a flat plaque lesion rather than a mass.
Oral melanomas in dogs are considered aggressive tumors and typically exhibit a high rate of metastasis to local lymph nodes and the lungs. Even with complete removal of the local oral tumor, approximately 80-85% of dogs with oral melanomas will go on to develop metastatic disease.
Nailbed Melanoma
The second most common location is the nailbed or subungual crest. These occur in 15-20% of dogs, again as a solitary lesion. Dogs often limp on the affected foot, or the owner has noticed swelling, bleeding, or discharge from the affected toe.
Subungual crest melanomas behave much like oral melanomas, with a metastatic rate equivalent to tumors located in the mouth.
Dermal Melanoma
Dermal melanomas most often appear as a darkly pigmented dermal mass and may be one or multiple. In rare cases, dermal melanomas may invade more deeply into the tissues or, even subcutaneous melanomas may occur.
Dermal melanomas confined to haired skin are benign in many cases and are therefore cured with complete surgical removal. Tumor location and a biopsy report will help in determining if additional therapy would be required following surgical removal.
Ocular Melanoma
Melanocytic tumors can manifest in the canine eye as eyelid and conjunctival masses. While many ocular melanocytic tumors in dogs are benign, they can cause problems with the eye as they develop. The majority of conjunctival, eyelid, and uveal melanomas are malignant. Malignant melanoma in dogs in other parts of the body can metastasize to the eye.
How is melanoma diagnosed in dogs?
If your veterinarian suspects that your dog has melanoma, they may perform a fine needle aspiration to collect a small sample of tumor cells or a biopsy to extract a portion of tumor tissue for examination. These samples are then sent to a lab for analysis, allowing your veterinarian to provide an accurate diagnosis of your dog's health condition. Additional diagnostic testing can help your veterinary oncologist optimize treatment and predict prognosis for melanoma, beyond the initial diagnosis.
Can melanoma in dogs be treated?
Many dogs diagnosed with early-stage melanoma can be treated successfully and go on to live full active lives.
Several different therapies or treatment combinations can be used to treat melanomas in dogs, including soft-tissue surgery, chemotherapy, immunotherapy, targeted therapies or palliative care when appropriate. Your dog's prognosis following a diagnosis of melanoma depends on a number of factors, such as the type of tumor, the tumor's location, and how advanced the cancer is.
The recovery time for a dog with melanoma can vary depending on the stage of the cancer and the treatment plan chosen by the veterinarian. In some cases, dogs may recover fully with treatment, while others may require ongoing care and monitoring.
Can melanoma in dogs be prevented?
While you cannot definitively prevent melanoma in dogs, there are steps you can take to reduce the risk. Regular veterinary check-ups and monitoring any changes in your dog's skin can aid in early detection and treatment of any suspicious growths or lesions that may develop. By being proactive and taking these preventative measures, you can help protect your dog from developing melanoma.
Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.