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Types of Tumors Seen In Dogs & How They Are Treated

Types of Tumors Seen In Dogs & How They Are Treated

Our Ambler vets know that finding a lump on your canine friend can be very worrying. Although many lumps are not cancer-related, there are a number of tumors that are common in dogs. Today we share some of the most common dog cancers and tumors, what to look for, and how they can be treated.

Tumors & Cancer in Dogs

Dogs are beloved members of our families and are frequently our most loyal of friends, and our veterinary team understands how distressing it can be to learn that your dog has cancer. While no one wants to think about their dog becoming unwell knowing what the signs of cancer are in dogs, could help you to spot the disease early when treatment is most effective.

While some tumors in dogs are linked to cancers that cannot be treated successfully, many forms of cancer can be treated and allow your dog to go on to live a good quality of life for months or years. Here are some of the most common types of tumors and cancers that our Ambler vets see in dogs, and how these tumors can be treated:


Typically seen in dogs under three years of age, Histiocytoma tumors are generally benign and rarely spread to other parts of the body.

Histiocytoma tumors are often referred to as button tumors because they are usually less than an inch in size, red, raised, and hairless. Often seen in English Bulldogs, Scottish Terriers, Greyhounds, Boxers, Boston Terriers, and Chinese Shar-Peis these tumors typically regress on their own within two to three months. That said, removal may be recommended for histiocytomas if they are particularly bothersome to your pet.


Papilloma tumors are benign tumors that look like warts in dogs, although they can be uncomfortable and problematic for your pooch. If an infection develops, multiple hard, pale, cauliflower-like warts may be seen on your dog's lips, inside the mouth, and around the eyes. These tumors can be painful and severe infections can make chewing and swallowing difficult for dogs with papilloma.

Papillomas generally go away after a few weeks, although it can take months. If your dogs has Papilloma tumors that are causing them discomfort your vet or veterinary oncologist may recommend surgery. Because these tumors are caused by a virus (papillomavirus) transmission can occur through direct contact with an infected dog or contaminated objects such as bedding or toys. Be sure to keep affected dogs isolated from unaffected ones, the incubation period often lasts months, so by the time symptoms make themselves known, it might have already spread to other dogs in a household.


Lymphoma is a very common form of cancer in dogs and there are more than 30 types of lymphoma which dogs can develop. In fact, lymphoma is a generic term used by vets to describe a group of cancers that stem from a type of white blood cell called lymphocytes that help the immune system to fight off infection. The most common types of dog lymphoma are, multicentric, alimentary, mediastinal and extranodal lymphoma. 

Signs of lymphoma in dogs include swelling under the jaw, in front of the shoulders and behind the knees. Lethargy, decreased appetite, and coughing may also accompany swollen lymph nodes.

Following a diagnosis of the type of lymphoma and staging, your vet may recommend chemotherapy to treat this form of cancer.

Mast Cell Tumor 

Mast cell tumors are one of the most common skin cancers seen in dogs. These tumors tend to grow quickly and can be red and itchy, and are often seen in short-faced dogs such as pugs, french bulldogs, and boxers. Shar-Peis are known to be susceptible to an aggressive form of mast cell tumors.

Surgical removal is the primary treatment for mast cell tumors in dogs, although depending on the location it can be difficult for your vet to ensure that the entire tumor is removed. If diagnosed early surgery can be a very successful treatment. That said, it is important to send the tumor to a pathologist to be graded in order to determine how aggressive the cancer is, and whether further treatments are required.


Melanoma tumors typically appear as darkly pigmented patches of skin. These tumors will often be found in and around the dog's mouth or on the dog's feet. Melanoma is prone to spreading quickly to other areas of the dog's body and tends to be malignant. Sadly these tumors will often metastasize to places such as the lymph nodes, lungs, liver, or other internal organs.

If your dog is diagnosed with melanoma the treatment recommended by your vet, or veterinary oncologist, will likely include a combination of surgery, radiation therapy, and immunotherapy.

Osteosarcoma (Bone Cancer) 

Osteosarcoma is the most common form of bone cancer in dogs. Although any breed can be affected by this type of cancer, our vets most often see osteosarcoma in larger breeds especially Greyhounds and Great Danes.

The primary symptom related to this form of bone cancer in dogs is limping.

Treatment for osteosarcoma in dogs is typically amputation of the affected limb followed by chemotherapy, however, in some cases if the tumor is detected early limb saving surgeries are available that involve the removal of only the affected area of the bone.


This form of cancer is very serious and requires emergency intervention or it may be quickly fatal!

Hemangiosarcoma tumors in dogs can grow quite large and are often found in the spleen, but may grow anywhere blood vessels are present and can spread to other organs, including the dog's heart and lungs.

Dogs with hemangiosarcoma tumors may show signs such as pale gums, labored breathing and an inability to stand up.

Treatment for hemangiosarcoma in dogs usually includes treatment to address internal bleeding, the surgical removal of the spleen, and chemotherapy following surgery.


This is a slow-spreading form of cancer in dogs but can be difficult to treat.

Amputation and radiation are commonly used to treat dogs with fibrosarcoma, in order to prevent a recurrence.

Signs & Symptoms of Cancer in Dogs

It can be difficult to detect signs of cancer by simply looking at your dog. In fact, even blood work often cannot detect certain cancers in dogs. That said, there are some signs that you can watch for that can indicate your dog may have cancer. As with people, early detection is the key to positive treatment outcomes when it comes to cancer in dogs. If your dog is displaying any of the following signs, make an appointment to see your vet as soon as possible. 

  • Sores that don't heal
  • Bleeding or discharge
  • Loss of appetite
  • Unexplained weight loss
  • Strong odor
  • Swelling
  • Lumps or bumps beneath the skin
  • Lethargy, depression, disinterest in exercise
  • Difficult or painful breathing or coughing
  • Straining when going to the bathroom
  • Challenges when eating or swallowing
  • Pain or difficulty walking, lameness or stiffness


It is essential to be aware of changes in your dog's behavior and pay attention to any bumps or lumps you may feel while petting and grooming your dog. If your canine friend is displaying one or more of the symptoms listed above, make an appointment to see your vet immediately.

Your Ambler vet may perform a biopsy or other diagnostics that will be sent to a vet lab for testing, as well as palpate your dog to feel for any lumps or bumps. Through testing and a thorough examination, your vet will be able to determine if your dog has cancer and what the best treatment options are.

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 dog's condition, please make an appointment with your veterinarian.

Contact our Ambler veterinarians if you think that your dog has a tumor. Our vets provide veterinary oncology services to diagnose and treat a range of tumors and cancers in dogs.

Caring for Pets in Ambler

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