What is Skin Cancer in Dogs?

What is Skin Cancer in Dogs

Skin cancer in dogs is the abnormal growth of skin cells. It is the most common type of cancer in dogs, accounting for about one-fifth of all cancer diagnoses. 

The types of skin cancer are classified according to the specific skin cells they affect. Since the skin has many layers and even more types of cells, there are many types of skin cancer. 

One of the reasons skin cancer in dogs is very common is that the skin is constantly exposed to the environment. The exposure is a plus for pet parents as it gives an opportunity to spot unusual growths during the early stages. 

What does Skin Cancer on Dogs Look Like?

Skin cancer in dogs can take on different appearances depending on the breed of your dog, stage, and type of cancer. 

The most common feature of skin cancer in dogs is a bump, lesion, or patch on the affected area. However, the appearance of the bump can vary widely. It can be soft or firm, large or small, raised or flat, and so on. 

Because skin cancer has no specific appearance, it is highly advisable to see a veterinarian as soon as you notice a persistent abnormality on your dog’s skin. 

What does Squamous Cell Carcinoma Look Like in Dogs?

Squamous cell carcinoma has the appearance of a firm raised bump that looks very much like a regular and being wart. 

The wart-like bump can grow basically anywhere on the body, but the most common sites are the dog’s abdomen and genitals. 

Types of Skin Cancer in Dogs


There are different types of skin cancer in dogs. To simplify things, let’s take a closer look at the most common ones. 

Fibrosarcoma. This is a malignant form of skin cancer that occurs in the fibroblasts (cells found in connective tissue like ligaments, tendons, and muscles). Fibrosarcoma affects the limbs and surrounding areas and can cause mobility issues.  

Fibrosarcoma is more common in middle-aged and older dogs but puppies can also be affected. Large breed dogs like Golden Retrievers, Irish Wolfhounds, and Gordon Setters have a higher risk of getting fibrosarcoma. 

Histiocytic Cell Tumors. These tumors start in the histiocytes, a type of immune cell found in different organs, including the skin. They can be benign or malignant. Malignant histiocytic (histiocytic sarcomas) are very aggressive and spread very quickly. 

Fortunately, malignant histiocytic sarcomas are rare. There is an increased risk of histiocytic cell tumors in older dogs and in giant breeds like the Bernese Mountain Dog. 

Mast Cell Tumors. As the name suggests, mast cell tumors in dogs start in the mast cells (immune system cells that modulate allergic reactions in the dog’s body). 

Mast cell tumors are the most common type of skin cancer in dogs, and they can be benign or malignant. Today, there are ways how to shrink a dog’s tumor, particularly mast cell tumors. 

Mast cell tumors mostly affect Beagles, Labrador Retrievers, Pugs, Boston Terriers, Boxers, Rhodesian Ridgebacks, etc. 

Malignant Melanoma. Melanoma in dogs is a skin tumor that grows in pigment-producing cells called melanocytes. 

Malignant melanoma is very aggressive and quickly metastasizes to surrounding organs, including the lymph nodes and internal organs. The tumors mostly affect the lips, mouth, and nail beds. 

Breeds most prone to malignant melanoma include Schnauzers and Scottish Terriers. 

Squamous Cell Carcinoma. Squamous cell carcinoma is a tumor affecting the squamous cells – the cells that make up the outer lining of the skin.

Squamous cell carcinoma is malignant and spreads to other parts of the body. Commonly affected sites are the head, lower legs, and abdomen. The exact cause is hard to determine, but sun exposure and papilloma infection are likely to play a role. 

Prone breeds include Beagles, Dalmatians, Bull Terriers, Basset Hounds, Bloodhounds, and Poodles. 

What Causes Skin Cancer in Dogs?

The exact cause of skin cancer is hard to determine, but there are factors that can increase your dog’s likelihood of getting cancer. These include:

  • Sun exposure. Ultraviolet (UV) rays from the sun can cause cancer of the skin, especially in dogs with light skin and short hair. 
  • Chemicals. Certain chemicals (shampoos, cleaning agents, and cosmetic products) that have carcinogenic ingredients can increase your dog’s risk of becoming more susceptible to g cancer.  
  • Infections. Some infectious agents (bacteria and viruses) can cause tumors. The perfect example is the Papillomavirus which causes papilloma tumors in dogs.
  • Lifestyle. Like many chronic diseases, skin cancer risk is heavily influenced by lifestyle choices, particularly inadequate diet and lack of physical activity. 
  • Genetics. Since certain dog breeds are predisposed to specific types of cancer. Namely, genetics can play a major role in the development of cancer in your dog. 

What are the Symptoms of Skin Cancer in Dogs?


The defining sign of skin cancer is a change in the appearance of the skin or a portion of the skin. This change can be a bump, lump, or patch in the affected area. Different types of skin cancer will result in different changes in skin appearance. Some of these include:

  • Raised firm wart-like lump for squamous cell carcinoma
  • Rubber-like sore for mast cell tumors
  • Hairless isolated lumps for histiocytoma
  • Dark-pigmented or non-pigmented lumps for melanoma
  • Toenail swelling and ulcers for nail bed melanoma

Secondary signs and symptoms of skin cancer include:

  • Limping or lameness 
  • Lethargy
  • Vomiting
  • Appetite loss 
  • Change in behavior
  • Weight gain or loss

While all these signs are great indicators of skin cancer, your veterinarian is the only person qualified to make an accurate diagnosis. Consult with your veterinarian as soon as you notice a change in your dog’s appearance and behavior. 

Diagnosing Skin Cancer in Dogs

Diagnosis of skin cancer often starts with fine-needle aspiration (FNA). FNA involves your veterinarian extracting a sample of your dog’s tumor cells using a syringe with a small needle. Then, the cells are examined under a microscope. 

In some cases, your veterinarian might perform a biopsy as well. A biopsy is more thorough as it examines a larger sample of the tumor mass. A chest x-ray may also be performed to check if cancer has spread to any vital organs. 

If necessary, your veterinarian will consult with a veterinary pathologist or refer you to a veterinary oncologist for confirmation of diagnosis and suggested treatment plans. 

How Do You Treat Skin Cancer in Dogs?


Treatment options for skin cancer include surgery, immunotherapy, radiation therapy, and chemotherapy. The best treatment for skin cancer depends on the type of tumor, stage of cancer, location of the tumor, and the dog’s characteristics like age and health status. 

Another important factor to consider about cancer in dogs treatment is cost. Treatments like surgical removal of tumors and radiation therapy can cost up to $5000 in operation costs and post-operative care.

In addition to the treatment, you, as a dog owner, can work to improve your dog’s health and wellness at home. 

Ask your veterinarian about holistic cancer treatment for dogs like diet, natural supplements, physical exercise, and CBD oil for dog cancer.

The Honest Paws CBD Range is made with full-spectrum hemp-derived CBD, a compound that has been shown to have positive impacts on health. The CBD products are perfectly safe for dogs, easy to use, and may help in the management of skin cancer in dogs. 

What can I do to Prevent Skin Cancer in Dogs? 

Cancer prevention, in general, is a complicated matter, but there are a number of ways you can lower your dog’s risk of getting skin cancer. Here are some tips in case you are want to know how to prevent cancer in dogs:

  • Limiting sun exposure. Protect your dog from direct sunlight, especially during very sunny afternoons. This is especially important to light and short-haired dogs as they have minimal protection from the sun’s UV rays. 
  • Using veterinary-approved products. Avoid using unfamiliar products on and around your dog. When uncertain, inquire from your vet about the safety of a product before using it on your dog. 
  • Healthy lifestyle. Encourage a healthy active lifestyle to minimize your dog’s risk of getting sick. A healthy lifestyle for a dog means a healthy, mostly whole food diet, regular physical activity, and high-quality pet products.
  • Regular checkups. The key to a good prognosis of any type of cancer is early detection. Take your dog for regular checkups by a qualified veterinarian to determine if your pet is in good health. 

While many of the factors that contribute to skin cancer in dogs are out of your hands, one still remains within your control – the quality of treatment your dog gets if it becomes ill. 

High-quality treatment is very costly, but with the right pet health insurance plan, you can get significant cover for the costs. 

For only $19.99 per month, the Ove Vet Insurance Plan gives unlimited access to a licensed veterinarian, $3000 per year in health coverage, and covers pre-existing conditions for six dogs. 

How Long Does a Dog Live With Skin Cancer?


A dog can live a full, healthy life if the cancer is caught and treated early. Mast cell tumors and histiocytomas tend to have a good prognosis, and with good treatment, a dog can still live a long life.  

However, dogs with malignant melanoma, fibrosarcoma, and squamous cell tumors have a poor prognosis. Dogs with malignant melanoma live for 1 to 3 years, while dogs with fibrosarcoma and squamous cell carcinoma rarely live for another year after diagnosis. 

Is Skin Cancer Fatal for Dogs?

It depends. If skin cancer in dogs is caught and treated early, it can be cured completely. However, if the cancer is not t managed adequately, it can be fatal.