Help! My Dog Has A Mouth Lump

Updated November 28, 2020

‘Essential facts (Details Below)’

When A Dog Has A Mouth Lump

  1. Oral masses have a high probability of being serious
  2. The sooner they are biopsied, the better the chances
  3. But don’t panic: many still turn out to be benign

Now dive deeper…

If you bring your dog to the vet for a lump in the mouth. you might get a surprise. Your vet’s relaxed, ‘let’s keep this under observation’ attitude is likely to change.

We’ve all seen too many dogs die of oral cancer. So although it might be benign, take your vet’s advice if they ask you to act quickly. Mouth lumps can be very, very nasty.

The Common Oral Lumps

Good news first. The most common mass is the least harmful.


Epulis (pronounced eh-pooliss) is the most common lump in the mouth of dogs. It’s a benign overgrowth of the gums, not involving the bone. It usually looks just like the pictures above or below.

bleeding lump dog mouth

We see epulides a lot in older dogs, especially with bad periodontal disease. And Boxers. Have a look in any older Boxer’s mouth and you should see plenty.

An epulis can still be harmful though:

  • It can cover the tooth and trap food, causing tooth loss
  • It can get big enough to interfere with chewing
  • It can be something nasty that gets called an epulis by mistake

The dog pictured above is a good example. Ted is young, has excellent dental care (raw bones!) and isn’t a typical breed. Therefore, I biopsied this mass for analysis and it turned out it wasn’t an epulis at all! See what it really was later.

Papilloma or Wart

dog tongue wart

Young dogs that socialise a lot often pick up papillomavirus and end up with warts on the head and in the mouth. Here’s a good example. The clue should be finding others elsewhere and the history. In this case, it was solitary so I biopsied it to be sure.

The one below has a more classic appearance.

dog wart in mouth

The Nastier Oral Masses

Next most likely are the ones we fear. These are especially common in older dogs. Early on they can just look like the picture at the start. However, they invade bone quickly.

Below are the results of attempting to surgically remove these lumps. As you can see, getting an accurate identification is the key to knowing what to do. Melanoma and osteosarcoma are usually not curable. Ameloblastoma, which often looks the same, has an excellent outlook. That’s why we will start with a biopsy, where we send a small piece away for analysis.

TumourPrevalence% Survival at 1 year
Squamous cell carcinoma17%91%

* also called an ameloblastic fibro-odontoma or acanthomatous epulis

Ted’s tumour, by the way, was an ameloblastoma. It has an excellent prognosis but needs extra surgery to remove it completely. The speed with which his owners got him checked means that it shouldn’t be too disfiguring.

dog palate lump

There are many other, rarer tumours of the mouth of dogs, too numerous to mention. However, I’ve included all the examples seen over a 25 year career.

Pictured is also the incisive papilla found on a dog’s hard palate just behind the upper incisors- this is normal.

Surgery For Oral Tumours

If the prognosis is good enough, we will recommend you to see a specialist surgeon. Removal usually also involves some of the jaw, but you’d be surprised how well they do afterwards.

There is no doubt that the chances of survival for any of these tumours will go up the earlier they are treated.

So if you see a lump, should you be like Ted’s owner? He could have ended up with a result that says there’s nothing to worry about. That might seem like a waste of money.

It wasn’t. Early intervention has made his lump curable. If we’d waited, that could have no longer been true.

You might also like: Common Skin Lumps Of Dogs

Have something to add? Comments (if open) will appear within 24 hours.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. Meet his team here. The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.

28 Replies to “Help! My Dog Has A Mouth Lump”

  1. 8 year old dog, marble sized mass appeared very suddenly (I believe overnight) in front of incisors. Needle aspiration from 3 locations in mass was inconclusive (only a few abnormal white blood cells). Pathologist diagnosis included everything from foreign body reaction to cancer. Next step is to sedate and remove a piece of the mass and send for a biopsy. My concern is she had a mass appear suddenly in the corner of her eye a year ago, planned for sedation and removal but it disappeared just prior to removal – about 6 weeks after appearing. It’s been about 4 weeks and the marble size mass has not changed in size. Does not appear to be bothered by the mass. Dont want to put her through the pain/cost of partial removal for biopsy if it could just be a reaction to something. Any thoughts?

  2. My parents’ dog is a 17 year-old Maltese. He has stage 4 periodontitis and been an obese dog for a while. He has been noted with a sudden red, large lump on the gum where his canine was extracted years ago. The vet is suspicious that the lump could be cancerous and would like to perform biopsy but my parents are reluctant as he is very old and loves to be home, and hospitalization and treatment mostly likely will stress him out a lot. Currently, he is taking abx and anti inflammatory med, and is doing a lot better with wet food but still has swollen gum.
    Given his age, would you say assessment and possible intervention for his gum would be worth it?

    1. Hi Hannah. It’s relatively simple to biopsy a mouth lump. If that’s all you want done, it shouldn’t cause much ill effect. If his quality of life is otherwise good it’s worth doing if your vets feel it’s safe.

  3. My dog is 13, 61 lbs, and I recently noticed a small abnormal growth on the inside of her mouth on the top of the mouth behind her molar. I noticed from a picture in May ’22 from another dog dental place that took a picture and the growth appears there as well. So she has had this growth that hasnt changed in size for a year and a half. Its in a place that is hard to get to so she has to be anesthetized and there may or may not be enough to get a biopsy. We are due for surgery to get as much of it removed and biopsy of the mass cut off next week. I am wondering though, would there be any possible complications with surgery and if it hasnt grown or changed in size for a year and a half, is that something I sohuld continue to monitor or do you recommend it to be cut off?

    1. Hi Donnie. It’s difficult to say without seeing the patient and photographs won’t help I’m afraid. Regarding complications, it’s all about the overall health assessment that your vets have already done, so the best thing you can do is follow their advice.

  4. Hi doc, are there are specific types of tumors/lumps that more commonly grow underneath the tooth? Curious about a case in which a dog’s tooth was removed and a mass of tissue was found underneath. It is getting biopsied but curious if this is more common in a specific type of oral cancer.

    1. Hi S. it could be any of the examples in this article, but also even just an inflammatory polyp.

  5. Hello, I have a Pitbull and he is 10 years old, we just notice he has a lump size of a quarter in his gum covering a tooth.
    He acts normal and eats, drinks water and does his necessities
    At the present time I cannot afford a Vet, what do you recommend me to do, please help.

    Thank You

    1. Hi Marina. If you can’t visit a vet, there’s not much you can do except observe the mass. The good news is that most of these masses will be an epulis and not require surgery, but please measure it monthly. If it’s changing in size you’ll need to find a vet regardless.

      1. I randomly found your website after Googling dog mouth sores after seeing photos of dog mouth sores on Reddit. I enjoyed reading through the comments, where you consistently responded to every question with focused recommendations! Whew, you’re amazing! You are (going to be?) a stellar doctor and your community is fortunate to have you!

  6. Hi! My doggo is 13, turning 14 in November. She is a toy poodle. She has a lump close to her mouth, on the gums. She has been takin pills for chemo for months, it gets better and than bad again. As shes old vet didnt recommend the surgery. Also, he said that it might grow in another place. Please, advice me sth. Looking forward to hearing from you. I am so very lost!

    1. Hi Melano. To this and any similar future comments, I am sorry that I cannot give any useful information until a biopsy has been taken and the mass identified.

  7. I found a lump on my dogs gum, just above his first molar. It looked like a blister at first, but each day it was changing. I definitely thought it was just a tooth or gum boil and took him to the vet within a week, with the intention of getting the “dental” problem fixed. Turned out it was a highly malignant melanoma, and if i hadn’t found it he could have died within 60 days. He had it removed immediately, and then 6 months of chemotherapy. So I advice always have them checked out.

  8. 7 month old American Great Dane has two puffy smooth flesh colored growths on palate by back tooth. It is pink just like his mouth and then black looking just like his mouth tissue with a smooth appearance. It does not look inflamed or as a swelling would. It gets smaller and goes to the throat after the two bump areas. He will have a biopsy in 8/25. I am hoping because it has such a normal appearance that it will be ok. My daughter, who owns the dog, has bile duct cancer and worries he has cancer too. Of course your thoughts always go to the worst possibility. Does this sound really worrying?

    1. Hi Lori. You’re doing the right thing in getting a biopsy, and that gives me the opportunity to say that in the meantime don’t be too worried, as it’s unlikely to be serious.

      1. My dog is 1 year old and has a large red swollen looking bump/lump on the back of his hard palate close to his throat opening. We noticed it the other day when playing, but not sure how long it’s been there. He is playing, eating and drinking all normally and we got a biopsy done a few days ago but it could take up to two weeks to find out results and I’m afraid of it getting worse by then. Very red, hard swollen lump on the roof of mouth near throat, with puncture prior to the biopsy, hoping maybe something got stuck under the skin?

      2. Hi Elyse. This is difficult to answer, and the biopsy is the best. If the results are inconclusive, it may need to be surgically explored or referred for advanced imaging.

  9. Our dog has a small pinkness in colour lump between his teeth top jaw it’s firm to touch and he doesn’t have any problems eating or drinking he had one of these about 2 years ago and the vet removed it he’s now 5 yrs old what can we do to treat it I’ve seen mouth wash or salted water tee tree oil would like your advice please

    1. Hi Stephen. None of the treatments you mention are likely to work. At this stage, a lump is usually best removed as it’s likely to get very large in your dogs lifetime

  10. My puppy has a quite hard incisive papilla, it actually looks like a tooth, and it’s kinda pointy! I also think it bothers him because his food is constantly getting stuck to the roof of his mouth and I has a hard time swallowing. Is there anything I can do to help him with this? And the article is very helpful cause I really thought my pup was an alien!

    1. Hi Doni. All you can do is choose food types to avoid this- kibble should be better than wet for example. However, I have never seen problems.

    2. Hi Doc, a couple days ago I noticed that my dog wouldn’t let me touch the one side of his nose and by his teeth and I finally got a good look at what was going on and he has a lot of Epulis going on, but I also noticed about the size of a marble a blue round cyst, and I wondered what you thought about the color? I took him the next day to my vets and they wanna sedating remove the masses and send them in for biopsy and I’m trying to come up with funds so I can get them removed asap and they can do a biopsy. The vet said be prepared that it could be cancerous. I don’t think at the age of almost 8 that I should try any kind of chemotherapy treatments. I don’t know how they do that in dogs, but I wondered what you thought about chemotherapy in a dog that’s almost 8. How do they do chemotherapy? Is it a pill or a shot? Lots of things rolling through my head and I’m very concerned. Thanks for your help or input.. Deb from Michigan

      1. Hi Debbie. I would definitely take one step at a time and get the biopsies done plus any lumps removed that seem appropriate. If you are considering chemotherapy, what’s very important is the exact identification of the tumour first, and then to find out the success rates against it. They can be very bad for some types of mouth lumps and so chemotherapy is only good in some situations.

  11. This was so helpful. My older dog 17 yrs old has a round mass inside her mouth. It looks like a cherry tomato. By reading this I completely understand. The funny thing is that does not interfere with get eating. She never misses a meal but I have to say that her teeth on the side where the cherry tomato resides gets infected and messes with get eyes. I can’t afford a vet so I am glad o read this and help her a lot more. She isn’t any pain and still jumps around like a puppy.

    1. You clearly didnt read the article. Be ajse it says to get it checked asap to avoid pain, discomfort, having it grow and possibly cause jaw removal. Get your pup to a vet. Unless you’re already prepared to lose her.

      1. You know she said hes 17 years old, I had my dogs teeth cleaned every year for 13 years and this last year it went from $160 to 1,200 dollars,, vets have become a joke. That’s why were all on here looking for help that makes sense

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