A Primer on Oral Tumors in Dogs: Is the Lump in My Dog’s Mouth Benign or Cancerous?

Oral tumors are common in dogs and range from benign masses such as viral papillomas to aggressive malignant tumors. 

Malignant oral tumors frequently recur and spread to other parts of the body, even with aggressive therapy.

A Primer on Oral Tumors in Dogs

Types of oral tumors

Benign papillomas are pink swellings on the gums or other parts of the mouth and have a “wart-like” appearance. 

Most malignant tumors appear as swellings on the gums that often ulcerate, bleed, and become infected. 

Symptoms of oral tumors

Other common signs include:

  • drooling
  • bad breath
  • tooth loss
  • and facial swelling

Many pets have:

  • difficulty chewing
  • swallowing
  • and eating.
  • swelling and pain in nearby lymph nodes

Further, tumors in the back of the throat are particularly painful and can prevent swallowing.

Oral melanoma is the most common malignant oral tumor in dogs.

Diagnosing oral tumors

Your veterinarian will start with a physical examination.

X-rays and CT scans may help detect whether tumors have invaded the bones and guide the surgery. Loss of bone next to the tumor usually indicates malignancy. However, only a biopsy can confirm the specific type of tumor.

Biopsies inform us if tumors will come back or spread to other areas. Pathologists at the lab will tell us if the tumor is benign(recur locally) or malignant (can spread).

Treating oral tumors

Benign viral papillomas usually regress on their own without therapy. 

Frequently, the surgeon will excise the tumor. However, It is often challenging to remove malignant tumors completely. Further, it may involve the removal of large pieces of the jaw bone. Therefore, chemotherapy, radiation therapy, and other more specialized treatments may be useful.

Surgery usually improves survival time if there is no evidence that cancer has spread to the lymph nodes or lungs.

Oral melanoma

Melanoma is a common oral tumor in dogs–it is cancer of pigment-producing cells.

Not all dogs show symptoms but signs of oral melanoma may include:

  • pigmented or flesh-color tumor
  • excessive drooling
  • difficulty eating or drinking
  • chewing on one side of the mouth
  • swelling
  • foul breath
  • bleeding

When diagnosing oral melanoma, your veterinarian might perform:

  • physical exam and history
  • blood work
  • fine needle aspirate and/or biopsy of the tumor and local lymph nodes
  • x-rays
  • CT scan or MRI
Oral melanoma treatment

Standard treatment options of oral melanoma in dogs include:

  • surgery
  • radiation
  • chemotherapy

Your veterinarian might include NSAIDs in combination with other treatments.


A melanoma vaccine is now available. The DNA vaccine treatment stimulates your dog’s immune system to fight off melanoma. 

Further reading: Canine Oral Melanoma

Related articles:
Oral Melanoma in a Dog: Laney’s Battle With Oral Melanoma

Further reading:
Melanomas of the Skin and Toes
Oral Tumors in Dogs – An Overview

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