Help! My Dog Has A Mouth Lump

‘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.

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.

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 are welcome below and will appear within 24 hours of lodging.
By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. These help topics are from a series regularly posted on email and Twitter. Subscribe via email here to never miss a story! 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.


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

  1. 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.

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