What is an oral tumor? (VCA Animal Hospital – Overview)

An oral tumor is an abnormal growth and unregulated replication of cells that occur within the mouth.

• A dog’s mouth, similar to our own, is made up of several different cell types; for example, there are epithelial (or skin) cells, bone cells, fibrous cells, and others all of which can become cancerous.
• Some tumors may grow slowly and do not typically spread, meaning they are benign, whereas others are aggressive and spread elsewhere (malignant tumors). (VCA Animal Hospital – Overview)

What types of cancer can a dog have in their mouth? (First Vet)

The most common types of oral cancer in dogs are:

• Melanoma
• Squamous cell carcinoma
• Oral fibrosarcoma

Oral Melanoma in Dogs

Melanoma is a tumor of melanocytes, which are pigment-producing cells of the body.

• Oral melanoma has been considered an extremely malignant tumor with a high degree of local invasiveness and high metastatic ability.
• Median survival times for dogs with oral melanoma treated with surgery are approximately 17 to 18, 5 to 6, and 3 months with stage I, II, and III diseases, respectively.
• The tumors can be pigmented (darkly colored) or non-pigmented (pink like gum tissue). They may appear nodular or cauliflower-like.
  • These tumors are often seen as swellings on the gums around the dog’s teeth or on the soft or hard palate.
  • Melanomas often form ulcers that bleed.
  • Secondary bacterial infection is a common complication.
  • This type of tumor may appear small but they usually extend deeper in the oral tissues and invade the surrounding bone.

Oral Squamous Cell Carcinomas in Dogs

An oral squamous cell carcinoma (SCC) is a malignant tumor affecting the cells that line the throat and mouth, including the tonsils and gum line.

• It’s the most commonly reported mouth tumor in cats, and the second most common in dogs. Oral SCC in both cats and dogs is locally aggressive, which means it will invade tissues close to the tumor.
• Bowen’s disease or Bowenoid carcinoma (multicentric carcinoma) is a type of SCC in which the tumors are confined to the surface of the skin and mouth. This type, however, is rare in cats and dogs.
• The cause of oral SCC has not been identified or fully established, but most experts believe it’s a complex combination of several factors – genetic, environmental, and hereditary.
• The tumors appear nodular or cauliflower-like and may be pink or discolored.
  • Some tumors break open and bleed.
  • Although they may appear small, these tumors usually extend deeper into the mouth tissues and may invade the underlying bone.

Oral Fibrosarcoma in Dogs

Oral fibrosarcoma’s originate from the fibrous connective tissues of the mouth.

• These are malignant, rapidly growing tumors. Recurrence is very high after surgery, and metastasis is very common.
• The tumors may appear as swollen areas within the mouth. They frequently ulcerate and become infected.
• Surgery to remove the tumor is the standard treatment of choice for fibrosarcoma’s. If adjacent lymph nodes are affected, they are also removed during surgery. (First Vet)