Cat Skin Cancer: Types, Causes, Treatment & Prevention

Just like dogs and humans, cats can get skin cancer. If your cat gets a skin cancer diagnosis, you'll likely have a lot of questions. What does skin cancer look like on a cat? Can it be treated? Is it malignant? Discover the answers to some of the most common questions about cat skin cancer, including the different types, its causes, how it's treated and how you can help prevent it.

What Causes Skin Cancer in Cats?

Skin cancer in cats is caused when normal cells grow out of control. It doesn't have any one cause; rather, it's usually due to some combination of genetic, viral and environmental factors. The cause varies depending on the type of cancer. Squamous cell carcinoma, for example, is a common skin cancer caused by chronic exposure to sunlight. This type is seen most often in older cats with white fur, and it occurs on the less-furry areas that have non-pigmented skin, such as the ears, nose and eyelids. Skin cancer can also be a result of genetic causes, such as mast cell tumors in Siamese cats.

What Are the Different Types of Cat Skin Cancer?

There are several types of cancerous skin growths in cats. Here's a partial list of some of the more common types:

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is a malignant cancer of skin cells. It occurs on sun-damaged skin where the hair is thinnest, and it causes skin ulceration and crusting on the ear margins, nose and upper eyelids. According to Atlantic Veterinary Internal Medicine & Oncology, SCC generally affects only one area of a cat's body.

Mast Cell Tumor

A mast cell tumor is a common malignant skin tumor that arises from immune cells called mast cells. They're usually solitary red nodules that most commonly appear on the head and neck.

Cutaneous Horn

A cutaneous horn looks exactly how it sounds — a horn-like structure on the skin. These horns are made of keratin, a protein that makes up hair, skin and nails. Horns may originate from a virus or other skin abnormalities, including sun-damaged skin. Cats infected with feline leukemia virus (FeLV) may develop horns on their footpads.

Fibrosarcoma

Fibrosarcoma is a common malignant tumor that arises from the cells that make up connective tissue. Fibrosarcoma is caused by underlying viruses or may occur spontaneously. Tumors can occur on the trunk, legs, ears or at a previous vaccination site.

Basal Cell Tumors

Basal cell tumors may be benign or malignant but are more commonly malignant in older cats. Siamese, Himalayan and Persian cats may be predisposed to basal cell tumors, and the tumors most often occur on the head, neck or trunk.

What Does Skin Cancer Look Like on a Cat?

Skin cancer can form lumps and bumps, ulcerate the skin and cause it to bleed or crust, or, in some cases, create a horn. It all depends on the type of cancer. If you notice a lump, bump or other abnormality on your cat's skin, have your veterinarian look at it as soon as possible. Your vet will likely need to take a biopsy of the abnormality and run tests on it to determine whether it's cancer, what type it is, and whether it's malignant (which means it can spread to other parts of the body). This information is critical so your vet can determine the best treatment options.

How Is Cat Skin Cancer Treated?

Treatment depends on several factors: the tumor type, whether the cancer has spread to other parts of the body (metastasized) and where on the body the cancer is located. In general, the earlier cancer is detected and treated, the better the prognosis.

If your cat requires treatment, options may include surgically removing the cancer, cryotherapy, radiation, chemotherapy, vitamins or a combination of these treatments. Many skin tumors in cats, if completely removed surgically, have an excellent prognosis and complete remission.

Can Cat Skin Cancer Be Prevented?

While you can't guarantee that you can completely prevent skin cancer in your cat, you can take steps to minimize the chance of your cat developing it:

• If your cat is white or has non-pigmented skin on their ears and eyebrows, keep them indoors and away from sunlit windows during the time of day when the sun is most intense. If they do go outside, apply cat-specific sunscreen to non-pigmented areas.
• Look out for any precancerous lesions and treat them as soon as possible. Your veterinarian is the best resource for distinguishing the origin of a skin mass and determining if additional testing may be required. Physical appearance alone does not indicate the seriousness of a skin mass.  However, if the mass does not freely move, bleeds or has an asymmetrical appearance it should be evaluated immediately by your veterinarian.
• Feed your cat a high-quality, antioxidant-rich food.
• Keep your cat at a healthy weight. If they're overweight, work with your vet to help them lose weight safely. Obesity predisposes cats to many types of cancers.

The good news is that skin cancer in cats can be successfully treated, depending on the case, and not all are malignant. In fact, some skin tumors are benign and don't require any treatment except for you to monitor them at home. Regardless, always have your vet check out any skin abnormalities on your cat. Keeping an eye on your kitty's health is a key part of giving them the love and attention they deserve.