Recurrent Acanthomatous Epulis Tumor in Dogs

Lili Duda, VMD
Last Modified: November 1, 2001

Dear OncoLink "Ask the Experts,"
Our 10 year old Irish Setter/St. Bernard mix had an Acanthomatous epulis tumor removed from his front right lower gum line. We found that the tumor had regrown extremely rapidly and is now much larger than the original tumor that was removed. It is now the size of a gumball. The original tumor was about the size of a pea.

We would appreciate any information you feel is important to help us determine the best treatment alternatives for our dog.
We thank you in advance for your help and consideration.
P & S

Lili Duda, VMD, Editor of the OncoLink Veterinary Oncology Section, responds:

Acanthomatous epulis is a benign, but invasive tumor of the oral cavity in dogs. It arises from the periodontal ligament, which is the tissue that connects the tooth root to the bones of the jaw. This means that the tumor that you see is literally just "the tip of the iceberg".

Completely removing the tumor is curative, and is the standard treatment of choice. This means removing the portion of the jaw (including the teeth, bone and all soft tissues) that contains all visible tumor plus usually one tooth on either side that appears "normal" (this is because the tumor extends microscopically beyond what can be seen with the naked eye). While this might sound very aggressive, dogs do extremely well with this type of surgery. The main side effect is cosmetic, which is an issue for the owners, not for the dogs!

These tumors are responsive to radiation therapy, with about 90% long-term control reported in several studies. Surgery is not required prior to treatment for this tumor type. Radiation therapy requires delivering multiple small doses of radiation over several weeks.

There is very limited information concerning intra-lesional chemotherapy for this tumor. One small report suggests this might be helpful, but it remains to be seen if this is supported by larger studies. This type of treatment typically involves weekly injections over several weeks, and requires anesthesia to adequately deliver the drugs into the tumor site.

If acanthomatous epulis is not treated, the tumor continues to grow over weeks to months. Large tumors can bleed, become infected, and make it difficult to eat (due to discomfort or mechanical difficulties). In general, the best time to treat any tumor is while it is still small.

Please discuss the above treatment options with you own veterinarian.