Oral Tumors - Peripheral Odontogenic Fibromas

What is a peripheral odontogenic fibroma?

Peripheral odontogenic fibroma (formerly known as fibromatous and ossifying epulis) is a benign, often slow-growing tumor that arises from periodontal structures (gums, ligaments, and bone). They can be further sub-classified as peripheral odontogenic fibromas and acanthomatus ameloblastomas.

 

What causes these types of tumors?

The reason why a particular pet may develop this, or any tumor, is not straightforward. Very few tumors have a single known cause. Most seem to be caused by a complex mix of risk factors, some environmental and some genetic or hereditary. Shetland Sheepdogs and Old English Sheepdogs may be predisposed to develop these types of tumors; however, no genetic or hereditary cause has been linked to their development.

 

What are the signs that my pet may have this type of tumor?

You may notice a distinct mass (tumor) or proliferation of tissue on your dog’s jaw or in his mouth. Masses start small but can continue to grow and become large. Acanthomatus ameloblastomas produce destruction of the underlying bone. This can cause a significant swelling in the region and also obvious pain. Your pet may exhibit signs such as excessive drooling, discomfort while eating or dropping of food, lack of appetite, difficulty closing and chattering of the jaw, or reluctance to be touched on the head.

 

How is this type of tumor diagnosed?

Fine needle aspiration (FNA) or biopsy is performed to diagnose peripheral odontogenic fibromas. FNA involves taking a small needle with a syringe and suctioning a sample of cells directly from the tumor and placing them on a microscope slide. A veterinary pathologist then examines the slide under a microscope. FNA may not provide enough information for a diagnosis, and a biopsy may be required. A biopsy is a surgical removal of a portion of the tumor. Pieces of the tumor are then examined under the microscope. This is called histopathology.

Dental X-rays of the region may indicate that the underlying bone is affected. CT scans of the head may provide the best insight as to how extensive the bone is affected and where the tumor begins and ends.

 

How do these types of tumors typically progress?

These tumors do not spread elsewhere. They are locally aggressive, meaning they tend to continue to grow and invade the adjacent tissues. This can continue to cause oral pain, movement or loss of teeth, and may end up affecting more than one side of the jaw if not treated.

 

What are the treatments for this type of tumor?

If the tumor can be easily removed, surgery is preferred treatment. This may involve removing a portion of your pet’s jaw (upper or lower). This may sound scary at first, but many pets experience pain with these tumors and after surgery, this pain is relieved.

Acanthomatous ameloblastomas are radiation responsive. The best control is surgery; however, if the tumor is too large, or if surgery is not preferred, radiation therapy is an excellent alternative.  

This client information sheet is based on material written by: Jan Bellows, DVM, Dipl. AVDC, ABVP; Christopher Pinard, DVM

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