Mouth Cancer (Ameloblastoma) in Dogs

Malignant canine ameloblastoma is a tumor that is from the bones used in supporting your dog’s teeth, and this type of tumor comes from the epithelial cells of your dog’s jaw. There are many kinds of cancers in dogs and several types of oral cancers, but malignant oral ameloblastoma is not common. The majority of oral ameloblastoma are not cancerous (malignant), so it may be tempting to ignore the growth in your dog’s mouth until it gets big enough to cause problems. However, it is important to your dog’s health that you never wait when it comes to any kind of growth or mass anywhere on the body.

Ameloblastoma masses are usually benign, but in a few cases, these tumors turn out to be malignant. A malignant oral ameloblastoma (mouth cancer), or canine acanthomatous ameloblastoma, is a fast growing cancer and spreads to the bone and teeth, but it does not usually spread to other parts of the body. While the average age of dogs who get this disease are over eight years old, these tumors have been found in dogs from age three to 19. This type of cancer is rare, but seems to be increasing rapidly, and experts believe it is because of the longevity of dogs with the advancements made in veterinary medicine.

The main symptom of malignant oral ameloblastoma is a lump or mass in the mouth which does not usually cause pain. However, the size of the mass can displace the teeth, which will cause pain and inability to use the mouth as usual.  These tumors have been reported to reach up to 20 cm and can get even larger than that. It is also common to see a multitude of tumors in the mouth. Some other common signs are:

• Bloody saliva or blood from the nose
• Excessive drooling
• Tooth pain
• Difficulty eating and drinking
• Refusing food
• Pawing at the mouth or face
• Chewing on one side of the mouth
• Loose teeth
• Enlarged lymph nodes in the neck

The cause of malignant oral ameloblastoma is still not known, although it is thought to be seen more in male large breed dogs (like German Shepherds and Golden Retrievers) and dogs that are of middle to old age (over five years old).

The veterinarian will do a comprehensive physical exam, which includes your dog’s vital statistics (weight, blood pressure, pulse, body temperature, blood oxygen level), and a detailed visual examination of the ears, eyes, and nose. The veterinarian will also do an extensive oral exam including the size of the tumor and lymph nodes in the area as well as swabs from the tumor and throat for laboratory analysis. The exam will also depend on you describing the symptoms you have noticed and when they began. You should also be prepared to provide your dog’s medical background, any illness or trauma, shot records, and any recent changes in behavior or appetite. 

Some tests your veterinarian may order will be blood work (complete blood count, blood gases, blood chemistry panel, and glucose test), radiographs (x-rays) of the chest and skull, fine needle biopsy of lymph nodes or tumor for laboratory analysis, and an endoscopy for a better look at the inside of your dog’s mouth and throat to be sure the cancer has not spread. The veterinarian will possibly need to get a CT scan, MRI, and ultrasound of the skull for a more detailed look at the tumor. The veterinarian will probably refer you to a veterinary oncologist for treatment.

The best way to completely get rid of a malignant oral ameloblastoma is to surgically remove it, which usually includes removal of a portion of the jaw as well. The oncologist will admit your dog to the animal hospital, and your dog will probably stay overnight after the surgery for observation. The surgery is relatively safe, with a few complications that can be expected with any surgery, such as anesthesia reaction or infection. In some cases, it may also be necessary for your dog to have chemotherapy or radiation therapy to be sure the cancer is gone.

While these types of tumors are not normally invasive to the rest of the body, if the cancer is not treated early enough, it can and will spread to the lymph nodes as well as vital organs. If your dog’s malignant oral ameloblastoma is treated before it spreads, the chances of recovery are good. Once the tumor is removed, and the doctor and oncologist both verify that your dog is cancer-free, your dog’s life expectancy will not be adversely affected at all. After your dog comes home, you will need to provide a safe and quiet place for your dog to sleep away from the rest of the family and pets. A follow-up visit will be necessary after about one month and another in six months just to be certain that the cancer has not returned.