Common Canine Oral Tumors

“Say cheese!” Your dog reluctantly obliged. Upon seeing your furry best friend open his/her mouth, you noticed a… lump! Seeing this had you thinking, “What could this gross lump be?” Well in this article, we are going to briefly discuss the most common tumours in dogs.

Before we dig into slightly deeper details, it is important to know that tumours can be classified as benign or malignant. To start, benign tumours do not invade nearby tissues or aggressively spread to other parts of the body. Usually, the outcome for benign tumours is very good. Below are the most common benign tumours in dogs:

Benign tumour #1 – Epulides

Most common benign tumour in dogs and can be further classified as the following:

Fibromatous epulides

These are usually pink, pedunculated, non-ulcerating masses and have relatively smooth surfaces.

Peripheral odontogenic fibroma

These look like the fibromatous epulides but have a bony composition to it.

Acanthomatous ameloblastoma

Cauliflower-like mass and usually has an ulcerated surface. This tumour is most commonly found in the incisor and canine tooth areas.

Benign tumour #2 – Eosinophilic granuloma

Usually appear as rough and ulcerated plaques found on the tongue surface.

Benign tumour #3 – Odontoma

This tumour is made up of tooth components and may or may not resemble a toothlike structure.

Benign tumour #4 – Viral papilloma

This is often seen in young dogs as a whitish, rough mass. This mass is caused by the papovavirus. As these lesions recede, they may turn dark gray. It should be noted that sometimes, this mass can develop to a more serious tumour, called squamous cell carcinoma (to be discussed later).

Now, you’re probably wondering, well, what could be worse than seeing these lumps in my dog’s mouth? Well, this is where the dreaded malignant tumours come into play. Malignant tumours are tumours that invade nearby tissues and can aggressively spread to other body parts/organs (e.g. Lungs). These tumours often carry a poor outcome. Below are the most common canine malignant tumours that we should all be vigilant of:

Malignant tumour #1 – Malignant melanoma

Most common oral malignant tumour in the dog. These are usually pigmented (although sometimes not and thus called amelanotic), ulcerated masses and can be found in your dog’s gums, inner part of the cheeks, lip, tongue, and palate. Male dogs with heavily pigmented mucous membranes are most commonly affected.

Malignant tumour #2 – Squamous cell carcinoma

This tumour arises from the outer layer (epithelium) of your dog’s oral cavity. It usually affects the gum, tonsils and tongue. Large middle – geriatric aged dogs are most predisposed. The lesions are cauliflower-like and ulcerated. It should also be noted that a variant of this tumour can exist in dogs that are less than one year of age and it is called papillary squamous cell carcinoma.

Malignant tumour #3 – Fibrosarcoma

This malignant tumour can be frequently found in the upper jaw (usually the upper 4th premolar tooth) of large, male, older dogs. Other growth sites for this tumour are the gums, palate, cheek, lips, and jaw bone.

Malignant tumour #4 – Osteosarcoma

Deriving from the word “osteo” which means bone, this tumour usually causes a severe bony invasion of the lower jaw (mandible), but can also affect the upper jaw (maxilla) and palate.

The information provided above is certainly just snippets to help you make an informed decision with regards to your dog’s oral health. Certain diagnostic procedures like blood counts, radiographs, ultrasound, lymph node or tissue excision/biopsies, may be indicated to arrive at a definitive diagnosis of a tumour. Treatments will also vary as malignant tumours will require a lot more effort and risks. Talking to your veterinarian would be a great first step to hopefully addressing your dog’s lumpy situation!

Written by: Raymond Reboja, DVM

Reference: Veterinary Information Network