An epulis is a lump growing from a dog's gums. The word is a general description, not a diagnosis: the American Veterinary Dental College defines it as a gum mass of any type.1 Most epulides are benign, but one common type, acanthomatous ameloblastoma, invades the jaw bone, and some cancers look just like a harmless gum lump.2,3 In one study of 403 dogs whose mouth lumps were biopsied at a dental referral practice, 37% had a malignant tumor.4 So any gum growth should be checked by your vet, and a biopsy is the only way to know what it is.2,3
At a glance
- What it is: a gum lump; the biopsy result gives the real name and decides treatment.1
- Most common types: acanthomatous ameloblastoma, peripheral odontogenic fibroma and focal fibrous hyperplasia.5
- Spread: these types don't spread to other organs, but ameloblastoma invades bone.2
- Treatment: surgical removal, sometimes with part of the jaw; usually curative when removed completely.2,6
- Related: signs of oral cancer in dogs and dog teeth and dental care.
Types of Epulis
Older names are still common, so you may hear more than one name for the same growth.2,1
| Type (older name) | What it does | Notes |
|---|---|---|
| Peripheral odontogenic fibroma (fibromatous or ossifying epulis) | Benign. A firm gum mass that grows from the tissue holding the tooth. Some contain bone-like material. | The most common benign mouth tumor in dogs. Complete removal appears curative.2,7 |
| Acanthomatous ameloblastoma (acanthomatous epulis) | Benign but locally aggressive; often invades surrounding soft tissue and bone. Doesn't spread to other organs. | About 70% occur in the lower jaw, mostly at the front, in adult large-breed dogs.2,8 |
| Focal fibrous hyperplasia | A reactive growth, not a true tumor. | Seen in somewhat older dogs, more often in the front of the upper jaw.5 |
| Gingival hyperplasia | An overgrowth of normal gum tissue, often along many teeth. | Not a tumor, but it can look like one in a single spot.9 |
How Common Are They?
- In a UC Davis series of 152 dogs with possible tooth-origin tumors, 45% had acanthomatous ameloblastoma, 31% peripheral odontogenic fibroma and 16% focal fibrous hyperplasia.5
- Acanthomatous ameloblastoma is described as the most common tooth-origin tumor in dogs.6
- In 403 dogs biopsied at a dental referral practice, 37% of mouth lesions were malignant, 34% were tooth-origin tumors and 28% were inflammatory. Referral practices may see more serious cases than a general clinic.4
Breeds at Risk
- Acanthomatous ameloblastoma: Golden Retrievers, Akitas, Cocker Spaniels and Shetland Sheepdogs were overrepresented in one study, and Golden Retrievers in another.5,6
- Gingival hyperplasia: Boxers most often, plus Bulldogs and sometimes Cocker Spaniels. A genetic component is suspected.9
- Peripheral odontogenic fibroma: no breed link was found.5 It's most common in dogs over 6.2
Why a Biopsy Matters
You can't tell from looking whether a gum lump is cancer.3,2 The three most common malignant mouth tumors in dogs, melanoma, squamous cell carcinoma and fibrosarcoma, can all look like a simple gum growth. Melanoma isn't always dark; some are pink or gray.2 Your vet will usually recommend a biopsy, dental X-rays to look for bone damage and, if cancer is possible, checks of the lymph nodes and chest.2,3 Even suspected gum overgrowth may be biopsied to rule out cancer.9 See signs of oral cancer, mouth cancer in dogs and melanoma in dogs.
Treatment
- Peripheral odontogenic fibroma: removal of the growth and the gum around it, usually with the involved tooth, and cleaning out the socket. Removing the tooth helps prevent regrowth.2,3
- Acanthomatous ameloblastoma: removal with a margin of normal tissue and bone, about 1 centimeter, which usually means removing part of the jaw (partial mandibulectomy or maxillectomy). Dogs generally eat and look good afterward, especially when the front of the jaw is removed.2
- Jaw reconstruction: some specialist centers rebuild the jaw after removal; in one series of 11 dogs, none had the tumor come back.8
- Radiation therapy is an option for large tumors in older dogs where surgery would be disfiguring. It works best for small tumors.2,10
- Gingival hyperplasia: surgical trimming of the extra gum (gingivoplasty), usually with a dental cleaning. It often grows back in predisposed breeds.9
- Recovery: soft food and no hard chews for about 10 to 14 days while the gums heal.3,9
Will It Come Back?
Recurrence after complete removal is uncommon. In a study of 263 dogs with acanthomatous ameloblastoma, none had the tumor come back after surgery intended to cure it, and the authors questioned whether wide margins are always needed.6,8 Peripheral odontogenic fibroma is cured by complete removal.2 Gum overgrowth is the exception: it often recurs.9
Medications That Can Cause Gum Overgrowth
Some medicines can make a dog's gums grow over the teeth: the immune-suppressing drug cyclosporine (the most common), calcium channel blockers used for heart and blood pressure, and some seizure medicines. Gums often return to normal when the drug is stopped, but never stop a medicine without talking to your vet.9
When to See the Vet
Book a visit for any new lump on the gums, especially one that's growing, bleeding, loosening teeth or making your dog chew on one side.7,3 Epulides usually don't go away without surgery. They're usually painless at first but can become painful if they invade bone or trap plaque.3 Regular dental checkups help catch them early.
Dog General Diseases and Symptoms QuickLinks
Frequently Asked Questions
Is an epulis in a dog cancerous?
Most epulides are benign and don't spread, but acanthomatous ameloblastoma invades bone, and some cancers look like a simple gum lump. A biopsy is the only way to know.
Should I have my dog's epulis removed?
Usually yes. Epulides rarely go away on their own, and removing them early is easier and more often curative. Your vet will also send the tissue for a biopsy.
What does an epulis look like on a dog's gum?
A firm, pink, smooth or bumpy lump on the gum, often near a tooth. Some are small and slow growing; others grow quickly and loosen teeth.
How long can a dog live with an acanthomatous ameloblastoma?
It doesn't spread to other organs, so dogs whose tumor is completely removed usually have a normal life expectancy. Left untreated, it keeps destroying the jaw bone.
Why are Boxers prone to gum overgrowth?
Gingival hyperplasia appears to have a genetic component and is most common in Boxers and Bulldogs. It's an overgrowth of normal gum tissue, not cancer.
Can a dog's epulis come back after surgery?
It's uncommon after complete removal. Gum overgrowth (gingival hyperplasia) is more likely to return and may need repeat trimming.
How can I tell an epulis from oral melanoma?
You can't reliably tell by looking, because melanoma isn't always dark. Your vet will recommend a biopsy.
Can medication make my dog's gums grow over the teeth?
Yes. Cyclosporine, some heart and blood pressure drugs and some seizure medicines can cause gum overgrowth. Talk to your vet before changing any medicine.
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Sources and further reading
This article was written and fact-checked on November 4, 2026 against current veterinary references and specialist guidelines:
- American Veterinary Dental College. AVDC Nomenclature. AVDC, updated January 2026.
- Mulherin BL, DVM, DAVDC. Oral Tumors in Small Animals. Merck Veterinary Manual (professional version), November 2024.
- Boldan M, DVM. Epulis in Dogs. PetMD, October 2026.
- Wingo K. Histopathologic Diagnoses From Biopsies of the Oral Cavity in 403 Dogs and 73 Cats. Journal of Veterinary Dentistry, 2018.
- Fiani N, Verstraete FJM, Kass PH, Cox DP. Clinicopathologic characterization of odontogenic tumors and focal fibrous hyperplasia in dogs: 152 cases (1995 to 2005). JAVMA 2011;238(4):495 to 500.
- Goldschmidt SL, et al. Clinical Characterization of Canine Acanthomatous Ameloblastoma in 263 Dogs and the Influence of Postsurgical Histopathological Margin on Local Recurrence. Journal of Veterinary Dentistry 2017;34(4):241 to 247.
- Reiter AM, DAVDC. Disorders of the Mouth in Dogs. Merck Veterinary Manual (pet owner version), updated June 2026.
- Tsugawa AJ, Arzi B, Vapniarsky N, Verstraete FJM. A Retrospective Study on Mandibular Reconstruction Following Excision of Canine Acanthomatous Ameloblastoma. Frontiers in Veterinary Science, 2022.
- Barnes C, DVM; Weir M, DVM; Barnette C, DVM. Gingival Hyperplasia. VCA Animal Hospitals, updated September 2025.
- Théon AP, Rodriguez C, Griffey S, Madewell BR. Analysis of prognostic factors and patterns of failure in dogs with periodontal tumors treated with megavoltage irradiation. JAVMA 1997;210(6):785 to 788.
About this article
Last updated : new page written using the American Veterinary Dental College, the Merck Veterinary Manual, VCA and published studies of canine oral tumors.
This page is for general information and is not a substitute for an exam by your veterinarian.
