Cancerous and Non-Cancerous Growths in a Dog's Mouth

Oral Masses (Malignant and Benign) in Dogs

An oral mass refers to a growth in a dog's mouth or surrounding head region. While not all growths (masses) are cancerous, oral tumors can become malignant and fatal if they are not treated early and aggressively.

Oral tumors can be found in the dog's lips, tongue, gums and lymph regions surrounding the mouth. The disease is treatable and has a high success rate when the tumor is discovered and treated early.

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the petMD health library.

Symptoms and Types

There are several signs of oral tumors, including:

  • Tooth movement or displacement
  • Oral sores or bleeding
  • Reluctance to chew when eating
  • Excessive drooling
  • Bad breath (halitosis)

While these are the most common signs, it is possible the dog displays no symptoms at all.


While the exact cause of an oral tumor is unknown, there are several potential risk factors, including secondhand smoke, and tooth and gum (periodontal) disease. In some cases, dogs that wear flea collars showed a higher incidence of oral mass development.

While an oral mass can be found in any breed, there are several breeds that are predisposed to developing the disease, including the:

In addition, older dogs are affected more often than younger dogs; males are also more predisposed to developing oral masses than females.


A biopsy will be performed to determine whether the mass is cancerous and to what degree. In addition to a biopsy of the mass, a biopsy is often performed on the surrounding lymph nodes to see if the disease has spread. X-rays may also be used to explore other parts of the body for symptoms. Non-cancerous oral growths have the greatest long term success once they are surgically removed.

  Next >