Melanoma isn't a condition that many pet owners worry about when it comes to their dogs, but skin cancer is a significant threat. Our Toledo vets discuss melanoma in dogs, as well as the causes, symptoms, and prognosis.
What is melanoma in dogs?
Melanoma is a cancer in dogs caused by the unregulated proliferation of melanocytes, a cell in their skin and mucus membranes. Older dogs are especially prone to this cancer, particularly its highly aggressive oral form. Melanoma of the mouth accounts for a large portion of all oral tumors seen in dogs.
Many pet parents ask their vets for pictures of melanoma in dogs to show them what to watch for. If you are curious, you could use your preferred online search engine and look up 'melanoma in dogs pictures.'
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 types of skin cancer can dogs get?
Dogs can develop many of the same types of cancer as people, and treatment is similar. Below are three of the most common skin cancers found in dogs.
Squamous Cell Carcinoma
Skin squamous cell carcinoma is dogs' most commonly diagnosed form of skin cancer. This form of dog skin cancer typically affects older animals and is often seen in Dalmatians, Beagles, Whippets, and white Bull Terriers. Squamous cell carcinoma appears as raised wart-like patches or lumps firm to the touch. These tumors are often found on the dog's head, lower legs, rear, and abdomen. While sun exposure may be linked to squamous cell carcinoma, there could also be a link to papillomavirus.
Malignant Melanoma
Melanomas appear as raised bumps, which can be dark-pigmented (but not always) and are often found around the dog's lips, mouth and nail bed. Many melanomas are benign. However, they can be malignant. Malignant melanoma in dogs grows quickly, has a high risk of spreading to other organs, and is a serious threat to your dog's health. The risk of developing melanomas is higher in male dogs than females, and certain breeds, such as Schnauzers and Scottish Terriers, also face an increased risk.
Mast Cell Tumors
Mast cell tumors are common in dogs and occur in the mast cells of the dog's immune system. These tumors, including the internal organs, can grow anywhere on your dog’s skin or body. However, some of the most common sites for mast cell tumors are on the chest, limbs, and lower abdomen. This form of skin cancer is most commonly seen in dogs between ages eight and ten years old. Certain breeds, including Boxers, Pugs, Rhodesian Ridgebacks, and Boston Terriers, appear to have an increased risk of developing this form of cancer.
What types of melanoma can dogs get?
Four types of melanoma have been found in dogs.
Oral Melanoma
Oral melanomas are some of the most commonly seen in dogs. Oral melanomas occur in the dog's mouth. They are typically seen in dogs ages ten 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 invasive, extending into underlying soft tissue and bone. Although many oral melanomas will exhibit dark pigmentation and appear black, 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 than a mass.
Oral melanomas 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 a small percentage 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
Melanoma in the dog's skin often appears as darkly pigmented dermal masses, which 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 hairy skin are often benign and can be cured with complete surgical removal. The location of the tumor and a biopsy report will help determine if additional therapy is required following surgical removal.
Ocular Melanoma
Melanocytic tumors such as eyelid and conjunctival masses can also affect the canine eye. While many ocular melanocytic tumors in dogs are often benign, they can cause problems for the eye as they grow. Most conjunctival and some eyelid and uveal melanomas are malignant. Malignant melanoma in other places of the body also has the potential to metastasize to the eye.
How is skin cancer diagnosed in dogs?
If your vet suspects that your pup could have skin cancer, they may perform a fine needle aspiration to take a small sample of the tumor's cells or perform a biopsy to take a portion of the tumor's tissue for examination. These samples are then sent to a lab to be analyzed. The results will allow your vet to provide you with an accurate diagnosis of your dog's health condition. Following the initial diagnosis of skin cancer, additional diagnostic testing to determine the extent of cancer in the body can help your veterinary oncologist to optimize treatment and more accurately predict prognosis.
Can dog skin cancers be treated?
Many dogs diagnosed with early-stage skin cancer can be treated successfully and go on to live full, active lives.
Different therapies or treatment combinations can be used to treat skin cancers in dogs, including surgery, chemotherapy, immunotherapy, targeted therapies or palliative care when appropriate. Your dog's prognosis following a diagnosis of skin cancer depends on several factors, such as the type of tumor, the tumor's location, and how advanced the cancer is.
Monitoring Your Dog's Health
Detecting the signs of skin cancer while the disease is still in its early stages is the key to good treatment outcomes. Familiarizing yourself with all your dog’s lumps, bumps, and rashes during your regular grooming routine and visiting your vet for routine wellness exams twice yearly can help catch skin cancers in their early stages.
If you notice an unexplained or unusual lump or bump on your dog or swelling around its toes, contact your vet.
Preventing Melanoma in Dogs
If you have a short-haired dog, you should apply sunscreen regularly whenever you go outside, especially on areas like their nose, which have no protection from fur. Look for sunscreens designed specifically for dogs, or ask your vet for recommendations. Be sure to avoid products with zinc oxide. It’s commonly found in sunscreen and is toxic to dogs.
You can also find dog clothing designed for sun protection and keep your pup in the shade as much as possible.
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.