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Causes of Lumps, Bumps and Masses in a Dog's Mouth

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Does your dog have a lump that concerns you? Learn about the types of benign and malignant growths that may develop in a dog's mouth.

Does your dog have a lump that concerns you? Learn about the types of benign and malignant growths that may develop in a dog's mouth.

What's That Bump in My Dog's Mouth?

Humans are not the only ones to get lumps and bumps on their bodies. Canines also frequently develop odd-looking masses and growths.

According to the Pet Cancer Center, oral cancer is the fourth most common cancer overall in dogs. A mass in the mouth can be caused by several conditions, but since there is always a chance that it is cancer, as in humans, any suspected lump or bump should be biopsied to rule out this possibility.

These Growths Can Be Hard to See

The problem is that owners don't always discover the growths. Sometimes, the growth is hiding under the tongue and can only be seen when the dog keeps their tongue to the side.

Sometimes the lump is in the back of the mouth or on the roof of the mouth. Often, one big cause of alarm is a bump on the roof of the dog's mouth right behind the top front teeth. This often turns out to be an incisive papilla, but at times there can be other growths in these areas, too.

Inspect Your Dog's Mouth Regularly

It is always recommended for dog owners to inspect their dog's mouth on a frequent basis. The best way to do this is by routinely brushing their teeth.

The following are some of the most common causes of lumps, bumps, or growths in a dog's mouth.

Causes of Benign Growths

As scary as growths can be, luckily many are benign. Regardless, all growths should be carefully evaluated by a vet to see whether or not they are harmless or need to be removed.

Here are some common causes of benign growths.


This is the most common type of benign growth found in dogs' mouths. It is also simply known as a gum boil. There are three types of epulis: fibromatous, ossifying and acanthomatous.

  • Appearance and Location: This growth is the same color of the gums and fairly smooth. It is typically found between the incisors or canine teeth. Sometimes it may present a stalk-like growth.
  • Who Gets Them: These lumps are generally found in older dogs over the age of six. The Boxer breed and other brachycephalic or short-nosed breeds may be predisposed to it.
  • Side Effects: As this mass enlarges, it may start causing trouble such as drooling, bleeding, difficulty eating, and bad breath. At times, the growth may cause the teeth to shift and grow misaligned.
  • Treatment: A vet will biopsy the growth to rule out cancer and will remove the growth surgically. Prognosis is pretty good for small epulis.

Canine Viral Papillomas

  • Appearance: These are small growths characterized by a jagged surface, resembling a cauliflower or sea anemone in shape. At times, however, they can be smooth.
  • Location: They are typically found on the lips and muzzles of dogs under the age of two. These papillomas are contagious between dogs and are transmitted with direct contact.
  • Treatment: Generally, they go away on their own within five months. While rare, some of these growths do turn malignant, according to Mar Vista Animal Medical Center.

Types of Malignant Mouth Tumors

These are the three most common malignant oral cancers found in dogs. Of dogs with cancer, melanoma affects 30% to 40% dogs, squamous cell carcinoma affects between 17% to 25%, and fibrosarcoma affects 8% to 25% according to Virginia J. Coyle, DVM, and Laura D. Garrett, DVM, DACVIM (oncology).

Malignant Melanoma

This is the most common oral malignancy in dogs. Oral malignant melanoma tends to develop when there is an abnormal cell division of melanocytes.

  • Location and Side Effects: It typically appears on the gums, the lip, the palate and sometimes on the tongue of older pets and can cause symptoms such as trouble eating (preferring soft foods), oral bleeding, facial swelling and bad breath.
  • Who Gets Them: Commonly affected breeds are those with pigmented mouth tissues such as the Chow Chow; however, other predisposed breeds are poodles, dachshunds, Scottish terriers and golden retrievers.

These tumors are known for spreading quickly and aggressively to other parts of the body, the preferred site being the lungs and regional lymph nodes.

Squamous Cell Carcinoma

This form of cancer is more common in cats; however, dogs occasionally get it, as well.

  • Side Effects: Affected dogs will drool, develop difficulty eating and have bad breath.
  • Location: This cancer has a prevalence for developing in the gingiva and is locally aggressive, but may spread late in the disease. If the mass is found in the front part of the mouth, there is a good chance that surgery can cure it, according to Vet Surgery Central Inc.


These are malignant tumors that are locally invasive but may spread to other parts of the body, a process known as ''metastasis."

  • Location and Appearance: These tumors originate from the fibrous tissue of the mouth and may appear as a red growth or ulcer. These tumors have a tendency to ulcerate and bleed but do not generally spread as quickly as other tumors.

Less Common Causes

Some less common but also malignant oral tumors found in dogs include osteosarcoma, mast cell tumor, hemangiosarcoma, lymphoma, plasma cell tumor and multilobular tumor of bone.

Always Get a Vet's Opinion

These are just a few examples of the most common oral growths found in a dog's mouth. Should your dog develop a lump, bump, mass, or growth in their mouth, no matter how small it is, it is best to have a vet take a look at it to rule out the possibility of cancer.

A possible squamous cell carcinoma of the lower mandible in a one-year-old Lab

A possible squamous cell carcinoma of the lower mandible in a one-year-old Lab

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: My 5 year old schnauzer has cauliflower growths around two of her lower teeth. No smell, no pain, no discharge. Bad sign?

Answer: If this mass in your dog's mouth looks like a cauliflower growth or an anemone, you may be looking at oral papillomas. Also known as warts, they are caused by the papillomavirus, a virus similar to the one that causes human warts. Was your dog in contact with other dogs in the past 1-2 months? Of course, see your vet for proper diagnosis and treatment. You can read more about these here:

© 2011 Adrienne Farricelli


Shelby on July 07, 2020:

She has a white bump in her mouth a little bigger than a pipeline . it new only a month or so doesn’t look like it’s getting right now have a vet appointment but not till 7/14

Adrienne Farricelli (author) on May 20, 2020:

Hi Margaret, so sorry your vet wasn't able to take a look in your dog's mouth. Sadly, sedation may be the only way to get a good look and perhaps even take a sample to see what it is. If your dog is need of anything else such a dental cleaning, this would be a good time to get this checked out.

margaret mckee on March 23, 2020:

11 year old jack and well bottom gum has pink coloured gum boil looking thing .he eats and plays with toys.took him to vet but wont let vet look in mouth .cost43 pounds.and vet didnt see there anything i could do to reduce size etc. vet will have to sedate him he is very nervous dog .help please.

Madison H on March 25, 2019:

My 6 month old Shi tzu has a bump on the side of his mouth on the lip. it is right in the skin lip line. There is no blood and he is eating, drinking and playing. I wish I could post a photo on here.

the bump is smooth, flesh-colored (pink like his inner lip) and almost looks like there is a puncture in the middle of it. (a hole maybe?) I can't tell if it is from a wound or if it something more serious. I am afraid to go to the vet because I am still a student and the vet can be very costly even just for a check up! I love my baby and want to make make sure he is ok while still being able to feed us.

Adrienne Farricelli (author) on March 15, 2019:

Margaret, how did the oncologist come to the diagnosis of tumor and what type of mouth tumor did the oncologist diagnose your dog with?

Margaret on March 10, 2019:

My Yorkie just made 16 in August I found a small lump on her lip having no insurance n lost my job I brought her into animal hospital in oct n oncology said it was a tumor that would spread to her lungs and organs it’s now March her tumor would swell up then dry out n she’d now in March it shrunk down no swollen lump w blood or shedding. Can u tell me why this happened n what’s the next step process if this was or is cancerous 8 months later she is still running around playful n eating .im confused to this diagnosis

Adrienne Farricelli (author) on February 04, 2019:

Debbie, if you haven't seen a veterinary oncologist, that would be a good step as these are specialists and can provide you the best advice. It sounds like your vet is just guessing. Yes, pet insurance is a blessing to those who can afford it.

Debbie on January 21, 2019:

My baby girl was diagnosed with diabetes in October. I've been doing so well with her on that front and shaking my head at the nay-sayers. My daughter's a type 1 (03/2018) and now lupus (01/2019). We've been busy on all sides but noticed a small something in Bella's mouth. Our old eyes didn't see anything out of the norm, few weeks past. Now it seems all of a sudden she's developed a huge tumor under her tongue, atop the lower jaw! Vet says lymph nodes are swollen, since it bleeds, rate of growth it's cancer! I'm dying inside. It doesn't seem to be bothering her. I don't want her to suffer but I don't want to lose her too soon. I was worried about diabetes! WTH I thought the vet could cut it off. She said jaw removal plus radiation treatment. Lots of money. My 28 year old daughter moved back in. Lots of money. Pet insurance. I'm preaching it to high heaven. Thanks for letting me share. Let me know if you have any tips or thoughts.

lisa on June 18, 2018:

my malamute 4 month pup has a cauliflower mass under his tongue I do not wish to spend a million bucks to tell me it's a zit. I wish vets could be a little more honest like human doctors. Instead of ripping off people because they can. I need the truth with out loosing my arm and leg to find out

Irène on April 22, 2018:

My little 4lb poodle as a lump growth between his teeth that were pulled by the vet...

it isn’t tender but is a fair size of it...

Can you give me any idea of what it is. on August 27, 2017:

My dog had epulis known as gum boils it was removed and was not canceres.but it grow back again spend a lot of $$ and put her thru hell. Any suggetions what to do?

Diane on August 26, 2017:

My German Shepherd one yr. old has a small white bump on his tongue. What is this?

Margaret Burke on April 22, 2017:

My boxer has developed black on his lower gums ??? Can you advise????

Leo on April 12, 2017:

Few days ago I just notice a mass on the side of my dog canine teeth . So I tried to open his mouth to figure it out,so I feed him water then a small piece of mass came out Form this mouth so I try to pulled it and the whole chunk of mass came out I was so glad . From that insident I always brush his teeth and check his mouth . But still the symptoms is there so if any one dog has recover form this can u give me tips pls.

heathar on August 09, 2016:

Our 7 month old pup has a growth under her tongue with white dot like bumps on one side and it appears to have white inside it. last seen by Vet two weeks ago and put her on watch. nothing changed. she has referred us to go to the University of Guelph to have this looked at. today she has started our pup on antibiotics to see if this helps. They are suggesting it could be a blocked gland.

Candice on June 06, 2016:

I have a two month old chihuahua, shih tzu mix. Just a few days ago i noticed a lump on the side of his face, cheek area. It seemed to be tender to the touch. Within a matter of a few days it seemed to swell up but didn't seem so tender. My husband checked the inside of his mouth and on the rear right side of his mouth was a lump that is red, with mild bleeding, sore the size of a tip of a qu-tip but is really swollen behind it. Just wondering what may have caused this and if there is anything we can do about it? Can this be serious and dangerous?

Adrienne Farricelli (author) on March 13, 2016:

It might be the incisiva papilla but not necessarily. Have it checked out by your vet to play it safe. Here's about the incisive papilla in dogs.

sandy on March 09, 2016:

We have a 3yr old german shepherd that seems to have a small bump just behind his top front teeth roof of his mouth. Is this normal?

A little background is he got into snail bait out in thecshed at 6 weeks old, we got him through this and a couple months ago he started having seizures. He is on phenobarbital but other than this he is good dog. He is the old fashioned german shepherd with straighter back and quite active.

Tim on August 19, 2015:

We have an 18 1/2 year old terrier mix with a fairly large gum boil between his lower lip and teeth. Fortunately, it does not interfere with his eating and he has a big appetite. He doesn't seem to be bothered with it except he often rubs the area on the rug. It sometimes bleeds but not severely. The vet doesn't seem to want to do anything about it. I was wondering how big these boils get and if there's anything I can do at home.

Adrienne Farricelli (author) on May 02, 2015:

Sorry, I really can't help, only your vet can tell exactly what it is. It's sort of like with human masses and lumps. Nobody can tell what a lump in a women's breast is and the same is with dogs. You'll find that even vets won't diagnose by looking at a lump alone, they'll have to do a biopsy to determine what it is. I hope it's something minor.

Alexandra on May 02, 2015:

Hi my dog has a rounded lump the size of a pea on his tongue. I just noticed it. It doesn't look sore. It's the same color as the rest of the tongue. Can you help please?

Adrienne Farricelli (author) on November 03, 2014:

At this age, cancer should be uncommon, but not unheard of, more common lumps are papillomas. Did the vet prescribe antibiotics and see if the growth shrinks? Can you have your pup go see a veterinary oncologist? A specialist may be better able to help you out.

jimal linder on November 03, 2014:

My thirteen month pup he is mastiff an chow chow mix he has a very big growth on his front lip I'm scared to death for him I took him to the the vet and they said it could be cancerous What more can I do I have his meds prescribed to him what do I do?

Adrienne Farricelli (author) on February 01, 2014:

Oh ,my what type of tumor? Did the vet do a biopsy on it? Does he have any other symptoms? Maybe get a second opinion. When my dog had a lump on her paw, I saw 3 different vets and they told me 3 different things. I used a free vet visit from VCA animal hospital too, so had nothing to lose. If you google VCA free exam, you can fill a form out and get a free visit if you are a new client. Also, a holistic vet can also help too.

josie on February 01, 2014:

I have a golden retriever he is 6yrs. old and yesterday the vet told me he has a tumor in the mouth. My Buddy is not feeling very well!! The vet told me that the best option is to put him to sleep!!! Not prepared for that one, love my dog and my kids are devastated!!! What can I do!!!

Adrienne Farricelli (author) on January 10, 2013:

The surgery may prevent cancer from spreading if caught in the early stages. That's what my vet said and why he removed it from my lab. Best wishes!

Andrea Foncerrada on January 09, 2013:

I have a 12 year old chow. She has a little mass on her tongue since last august. We decided not to do any surgery until it was absolutely necessary. It might be time because she is starting to have difficulty eating. If it is cancer, we won`t do chemotherapy or other treatments. We are only concerned of increasing her quality of life. Will the surgery increase it or decrease it? Any help?

Adrienne Farricelli (author) on October 18, 2012:

I hope it turns out being just a papilloma, fingers crosses. Lumps and masses in dog mouths can be scary.

Mollysmom on October 17, 2012:

I have a wonderful golden named Molly, she just turned 7yrs. old 10/11/12. We took her to the vet 3 wks ago, because she has a white round growth towards the tip of her tongue, vet put her on Pregnazone steroids, says he's 95% sure its cancer, I'm holding out hope that its some type of a viral wart Thank god she has no fluid coming from it, no bad breath, no problem eating or drinking, so we're hoping for the best. A needle bipsy is going to be performed this Fri.10/10, hoping for the best.

Adrienne Farricelli (author) on June 28, 2012:

So sorry to hear that. The vet offered no option of removing the mass in your dog's mouth surgically?

Lab Owner on June 25, 2012:

My 11 year old labrador has a growth on his top gum mouth and it's growing into the roof of his mouth. He had a tooth removed as the vet believed that it was irritating the growth. That growth has now doubled in size. She has assured us that it wasn't cancerous in any way shape or form. My labrador is now very ill as this growth has length sessions of bleeding every now and again. He has been sick, bringing up old blood, fresh blood from the growth and a white fluid. He's very lethargic and is showing signs of anemia. If there is no improvement, we will be letting him go tomorrow.

Adrienne Farricelli (author) on December 31, 2011:

Linda, don't over worry, the lump does not have to necessarily have to be something worrisome. My vet assumed the worst but then it turned out being only an oral papilloma. I know it is easier said than done, but try to relax and wait for Monday. If she is young and you just noticed this, chances are good it may be nothing major. Fell free to post back your vet's finding to share with others in your same situation. Best wishes!

Linda on December 31, 2011:

I just noticed a red mass in the back of my lab's mouth. Her breath has been bad lately but associated it with her snacking on deer droppings in our back yard. The more I read the more I cry. I will get her to the vets on Monday. Also last night after playing and running i noticed her breathing wheezing. With wjat is in tbe back of her throat it now makes sende. Anyone have seen this or cooments while I wait to get her to the doctor. Thank you and happy new year 2012.

Adrienne Farricelli (author) on December 23, 2011:

Alicia, my vet tentatively assumed the worse, but after removing the lump noticed its jagged surface and said it was a papilloma.

Alicia Nuss on December 23, 2011:

My lab has a mass under her tongue and others about her body .The one in her mouth looks very similar to this pic, thanks, now I am afraid to take her to the vet again she is my baby.Pug Lady I am so sorry about ur baby.Waggin Tails Mobil Pet Grooming

MarloByDesign from United States on October 09, 2011:

puglady, that breaks my heart. I am truly so very sorry.

puglady on October 08, 2011:

3 1/2 weeks ago my 12 yr. old pug had her teeth cleaned and an epulis removed. Vet did chest x-ray and told me 'best heart he's ever seen in an older pug'. Lab work came back perfect !! Thyroid, etc...all 'normal range'.

Noticed a few days ago difficulty eating and lymph nodes swollen . Opened mouth and saw LARGE growth on roof of tongue!! Just got back from vet. He was shocked. Immediately diagnosed with 'oral cancer'. I will being putting my baby girl down on Monday.

SUSIE DUZY from Delray Beach, Florida on June 07, 2011:

Thanks for this good information.

Maria Jordan from Jeffersonville PA on June 07, 2011:

Thank you for this well written information. A student recently discussed a mass that was found in her dog's mouth, and the picture was unbelievable. I will share this with her as well.

Voted UP & USEFUL!

MarloByDesign from United States on June 07, 2011:

Thank you for writing a Hub to help make dog owners aware of these canine mouth issues - as a dog lover, this is great. Please feel free to visit my Hub on 'Saving Money for Dog Owners'. Rated your Hub up and awesome.