Epulides/epuli (plural of epulis) are common benign growths found in dogs' mouths.

There are three types:

• peripheral odontogenic fibroma (previously called fibromatous epulis);
• peripheral odontogenic fibroma-ossifying type (previously called ossifying epulis);
• and acanthomatous ameloblastoma (previously called acanthomatous epulis).

Peripheral odontogenic fibroma was confirmed with biopsy. Courtesy Dr. Jan Bellows

Peripheral odontogenic fibroma and peripheral odontogenic fibroma-ossifying type are benign (not cancerous). They tend to be more common in males, and during middle age. They are not usually ulcerated or invasive. They look similar to gingival hyperplasia. They commonly occur as a reaction to trauma (tooth rubbing on the gum in brachycephalic animals, for example). 

Acanthomatous ameloblastoma is locally invasive and tends to destroy the bone. It usually does not metastasize (spread to other areas). 80%-90% of dogs with this form will have radiographic (X-Ray) evidence of bone damage.

Statistics

Fibromatous epulis is the most common epulis (57%), followed by ossifying (23%), and acanthomatous (18%).

Clinical Signs

Signs include a lump on the gums, drooling, bloody saliva, halitosis, facial deformity, and other signs of mouth injury. A visible lump is the most common sign.

Diagnosis

Diagnosis begins with a visual examination of the mouth.

Radiographs of the head can determine how invasive the tumor is.

Biopsy and histopathology of the lump will determine which type of epulis is present.

Treatment

Surgical removal, with or without cryosurgery or electrocautery, is the most common treatment for peripheral odontogenic fibroma and peripheral odontogenic fibroma-ossifying type.

Because of the invasiveness of acanthomatous ameloblastoma, surgery, radiotherapy, and chemotherapy are usually necessary. Surgical removal of the affected parts of the jaw is usually required.

Aftercare

After surgery, your veterinarian may instruct you to feed your pet a softer diet.

Prognosis

The prognosis (likely outcome) varies.

Peripheral odontogenic fibroma and peripheral odontogenic fibroma-ossifying type usually have a better prognosis than acanthomatous ameloblastoma does.

The prognosis for acanthomatous ameloblastoma is worse because of the amount of bone damage that the tumor causes and the amount of treatment required to control it. Part of the jaw may need to be removed to get all of the tumor.

The less tissue involved, the better. The more extensive the lesion, the more effect it can have on the dog’s quality of life.

Most of these tumors don't recur if the entire tumor has been removed. However, some can. Checking your dog's mouth frequently will help spot any tumor recurrence or new tumors.