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Could the Bumps on My Dog's Skin Be Skin Cancer?

Could the Bumps on My Dog's Skin Be Skin Cancer?

While our dogs are covered in fur, skin cancer is a very serious health concern for our canine friends. If you've found an unusual bump on your pooch's skin, it's always best to have it examined. Today, our Thousand Oaks veterinary oncologist explains three types of skin cancer commonly seen in dogs. 

Lumps & Bumps on Your Dog's Skin

Have you discovered a lump, bump or discolored patch of skin on your four-legged companion? If so, you're bound to be concerned about cancer.

Skin cancer can afflict dogs, just like it can humans. In fact, skin tumors are the most commonly diagnosed type of tumor in canines, partly because we can more easily spot skin tumors with the naked eye than other kids of tumors, and partly because the skin is exposed to more environmental factors that can cause tumors, such as solar radiation, viruses and chemicals than your dog's internal organs. 

It's important to note that not all lumps and bumps are cancerous. For those that are cancerous, many are treatable if detected early. 

If you've found a suspicious mark, lump or bump on your dog's skin, contact our board-certified veterinary specialists as soon as possible to book an examination for your dog. Successful treatment outcomes depend in large part on the early detection of cancer. 

Causes of Skin Cancers in Dogs

Skin cancer can be caused by numerous factors and triggers, including:

  • Genetics
  • Excess sun exposure
  • Hormonal abnormalities
  • Certain types of viruses 
  • Chemicals in the environment

Types of Skin Cancer in Dogs

Squamous Cell Carcinoma

The most commonly diagnosed form of skin cancer in dogs, skin squamous cell carcinoma typically impacts older animals and is often seen in beagles, white bull terriers, whippets and dalmations. These tumors appear as lumps that are firm to the touch or raised wart-like patches that are most often discovered on a dog's head, abdomen, lower legs and rear. Sun exposure may be a cause of squamous cell carcinoma. However, there may also be a link to papillomavirus. 


Often found on the limbs, this type of tumor can invade nearby structures, sometimes impeding their function.These and spindle cell tumors develop in the skin's connective tissues and beneath the skin. They grow slowly and may have a varied appearance, but tend to recur after being surgically removed. 

These tumors may also bleed, ulcerate and become infected. Fortunately, they rarely metastasize. 

Fibrosarcoma typically impacts middle-aged and older dogs, with an average age of 10 years. Young dogs can sometimes be afflicted with an aggressive type of fibrosarcoma. 

Histiocytic Cell Tumors

When this type of skin cell proliferates into tumors, they are called histiocytic cell tumors. Relatively common, these tumors typically impact dogs 3 years and up, especially boxers, boston terriers, Chinese shar-peis, greyhounds, Scottish terriers and bulldogs. 

There are actually three types of histiocytic cell tumors: histiocytomas are the most common. Systemic histiocytosis primarily afflicts Bernese mountain dogs, while malignant histiocytosis also impacts Bernese mountain dogs and appears in the internal organs first. 

Malignant Melanoma

These raised bumps can be dark-pigmented (but not always) and are often found around a dog's mouth, lips and nail bed. While most melanomas are benign, malignant melanomas are a very serious threat to a dog's health. These tumors grow quickly and have a high risk of spreading to other organs. Scottish terriers and schnauzers appear to face an increased risk of developing melanoma. Male dogs are more at risk than females. 

Mast Cell Tumors

Another very common tumor in dogs, mast cell tumors occur in the immune system's mast cells and can grow anywhere on the skin, and even on a dog's internal organs. Some of the most common sites for mast cell tumors to appear on are the chest, lower abdomen and limbs. Any breed can experience this form of skin cancer. However, it's most often seen in pugs, boxers, Rhodesian ridgebacks and Boston terriers between 8 and 10 years old. 

Diagnosing Dog Skin Cancers

To diagnose skin cancer in dogs, your vet may perform a biopsy to take a small sample of the tumor's cells for examination. This sample will be analyzed at a lab in order for your veterinarian to provide you with an accurate diagnosis of your pup's condition. 

In order to determine the extent of your dog's cancer, additional diagnostic testing may be recommended. This can help to optimize treatment and give a more accurate prognosis for your pet.

Treatment for Skin Cancer in Dogs

Veterinary oncology is a sub-specialty of veterinary medicine that deals with the diagnosis and treatment of cancer in animals. Many early-stage dog skin cancers can be treated successfully, allowing pets to continue living comfortable, happy lives for years to come.

If your primary vet suspects your dog may have cancer, you can be referred to our veterinary cancer specialist at VSEC who diagnoses and treats cancer in pets. You and your dog will meet with our oncology vet team for a consultation. The vet oncologist will then review your pet's health history, perform a comprehensive physical exam and recommend diagnostics, if necessary. 

Your dog's skin cancer treatment could include surgery, chemotherapy, immunotherapy, targeted therapies, or palliative care when appropriate. When it comes to the prognosis and treatment for skin cancer in dogs, options will depend on a number of factors, such as the type of cancer, the location of cancer, and how advanced your dog's cancer is.

Monitoring Your Pet's Health

The key to good treatment outcomes is to spot the signs of skin cancer while the disease is still in its early stages. During your regular grooming routine, familiarize yourself with all your dog’s normal lumps, bumps, and spots so that you can spot changes in your pup's skin right away.

Visiting your vet for routine wellness exams, even when your dog appears perfectly healthy, can help to catch skin cancers in the early stages.

Whenever you notice an unexplained or unusual lump or bump on your dog, or if you notice swelling around your dog's toes consult your vet right away and ask for a referral to our oncology vet team if needed. When it comes to your pet's health it's always better to err on the side of caution. 

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.

Our veterinary team at VSEC in Thousand Oaks offers diagnosis for dogs with cancer. Contact us today to book an appointment.

New Patients Welcome

VSEC Thousand Oaks is accepting new patients! Our board-certified specialists and experienced emergency veterinarians are passionate about restoring good health to animal companions.

Contact (805) 492-2436