Dogs are our best friends. When they develop skin cancer, it can be scary and stressful for both them and us. Fortunately, there are many things we can do to help. Let’s take a look at what cancer in dogs’ skin looks like, the different kinds of cancers that can appear on their skin, and what you should do if you spot symptoms on your pup.
Most Common Cancer in Dogs
Skin cancer is the most common type of cancer in dogs. It’s caused by the abnormal growth and spread of cells in your pet’s skin. Skin cancers can be benign or malignant, with melanomas being the most dangerous form of canine skin cancer. The most common type of dog skin cancer is mast cell tumor (MCT), which accounts for about 30% of all tumors found on dogs’ bodies.

If you notice a change in your dog’s appearance or behavior, it could be a sign that they have MCT, so it’s important to schedule an appointment with your veterinarian right away if you think this might be an issue!
Skin Tumor Causes
Skin tumors are caused by the abnormal growth of cells in the skin. The term “tumor” refers to any benign or malignant tumor that arises from any portion of the skin, including areas external to it such as fur. Skin tumors can be caused by UV radiation from sunlight, chemicals and other environmental pollutants, viruses, bacteria, fungi and parasites.
Benign or Malignant?
Benign tumors and malignant tumors are two different types of skin cancer in dogs. Benign tumors are not cancerous, but still grow and spread to other parts of the body. Malignant tumors are cancerous, and can grow quickly into life-threatening masses that invade nearby organs and tissues.
The difference between benign and malignant cancers is that a benign tumor will not spread outside its original location; it is contained within its own boundaries, while a malignant tumor has the potential to grow outward through your dog’s system into other parts of his or her body.
Mast Cell Tumors in Dogs
The most common type of dog skin cancer is mast cell tumor. Mast cell tumors are usually benign and grow slowly, but if you notice that your dog’s tumor becomes painful or large, consult your vet as it may be malignant (cancerous). The most common locations for these tumors to occur are on the head and neck, ears, chest, abdomen, and legs.
Melanoma in Dogs
Melanoma is another type of dog skin cancer that is more aggressive than other types of skin tumors. It develops in the pigment cells (melanocytes) in your dog’s skin, and its most common location is on either side of the muzzle. Melanoma can also appear on a dog’s lips, eyelids, ears and tail base.

The risk factors for melanoma include:
- Having light-colored or white fur
- Breeds prone to melanoma
Lumps on Dogs
Some signs that there is cancer in dogs skin include a lump or bump, a sore that doesn’t heal, changes in the texture of their skin, and changes in existing moles or freckles.
A lump on their body can be either raised above the surrounding area or sunken into it. It may have an irregular shape and feel different from other areas of your dog’s skin. Some lumps are painful, while others are non-painful.
The size of the lumps can vary greatly depending on what type of cancer they’re caused by; some are only as big as a pea while others can be several centimeters across!

Changes in your dog’s existing moles or freckles may also be signs of cancerous growths under the surface like melanoma (a more aggressive form than standard moles).
For example: if one were to appear suddenly where none existed before—or if one were larger than usual—then these could be warning signs worth investigating further by taking your pet for regular checkups by an experienced veterinarian who specializes in dermatology (a specialty within veterinary medicine).
Fine-Needle Aspirate
To diagnose dog skin cancer, your vet may perform a fine needle aspirate (FNA) to take a sample from the tumor for testing. FNA is a procedure that uses a needle to extract a sample of tissue from the tumor. The sample is then examined under a microscope by your veterinarian to determine the type of tumor and whether or not it contains cancer cells. This test is painless for dogs and humans alike.
Treatment for Skin Cancer
There are many treatments for dog skin cancer depending on the type and stage of their tumor. Surgery is usually the first step in treatment, but it can be expensive and some dogs do not respond to surgery well. Chemotherapy, radiation therapy and immunotherapy are also common treatments for skin cancers in dogs.
It’s important to remember that these types of treatments are very expensive—they average around $5,000 per year—and that not all dogs respond positively to them either. For example, one study found that only about 50 percent of dogs who received chemotherapy were still alive after three years!
Skin Cancer in Dogs
Even though there are many treatments for skin cancer in dogs, the key is to catch it early before it spreads. If you notice any changes in your dog’s skin, take them to see a vet immediately.
Read more:
Spontaneously occurring melanoma in animals and their relevance to human melanoma – PMC
5 thoughts on “Cancer in Dogs Skin”