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Lumps and Bumps and Cysts, Oh My! What To Do When You Find A Mass On Your Dog

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While it may be shocking and frightening when you’re petting your dog (like you always do) and find a lump or bump where it doesn’t belong, these are actually quite common in dogs, and not always something to worry about. Before you panic, read this article below from Dr. Mark Thompson of PetPlace.com to learn what do you when you find a mass on your dog.

Lumps and Bumps and Cysts, Oh My! What To Do When You Find A Mass On Your Dog

Skin growths are lumps of tissue that are within the skin or can be felt under the skin. Dogs can develop small bumps (papules) or larger bumps (nodules) on their skin. These lumps and bumps are fairly common occurrences, especially in the older dog.

Very often the word “lump” brings the word “cancer” to mind. However, there are many other causes of lumps. A skin growth or mass may be a malignant or benign tumor, an abscess, a cyst, a hematoma (blood-filled mass) or a reaction by the skin to an allergen (hives). Lumps are often benign accumulations of fat called lipomas. However, all lumps should be evaluated for the possibility of malignancy.

What to Watch For

Any new lump or bump should be evaluated right away, especially a lump that is rapidly growing, is warm or painful, is ulcerated or bleeding, is irregular in shape or is well attached to the tissues under the skin. Any of the above signs should prompt you to seek veterinary attention.


Your veterinarian may take a complete history. Expect to answer the following questions:

  • How long the growth has been there?
  • Has it gotten larger or smaller or changes in appearance?
  • Does the lump appear to be attached to the underlying skin?
  • How fast is it is growing?
  • Have there been any recent injuries or injections?
  • Is there only one lump or are there others?
  • Are there any changes in your pet’s behavior, such as eating less, weight loss, vomiting, diarrhea or lethargy?A complete physical exam will be done. Your veterinarian will pay particular attention to the appearance of the mass, whether it is hot or painful, whether it is within the skin or under the skin, if it is attached to underlying tissues and where it is located on the body. Additional tests may include:
  • An aspirate of the mass with a small needle may be done to collect cells for staining and examination under a microscope (cytology). This test usually requires no anesthesia and often leads to a diagnosis.
  • If the mass is ulcerated or draining fluid, a microscope slide may be touched to the fluid to make an impression for microscopic examination.
  • A biopsy may be taken to send to a veterinary pathologist for examination. The biopsy may involve removing the entire mass or removing a piece of the mass.
  • A piece of tissue may be submitted for culture if infectious agents such as bacteria or fungi are suspected.Treatment

    Treatment depends on the cause of the mass. There is no specific treatment for all skin growths.

    Home Care

    Give all medications as instructed and observe masses closely for growth, heat, redness and pain.

    If the growth has been removed or biopsied, keep your dog confined to allow for healing. Observe the incision site closely for drainage, swelling, redness, heat or pain.

Read more about what to do if you find a mass on your dog here. Have you ever found an unusual lump or bump on your dog? Tell us your story in the comments below!

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  1. Avatar Of Barbara A

    Barbara A


    I have a ten year old Maltese and I just noticed that at the point where her tail meets her body there is a fatty substance under her skin that completely circles her tail. Is this normal? I haven’t taken her to the vets yet because I just noticed it and will make an appointment next Monday. It’s not draining and it’ not hot to the touch. When I touch it, she doesn’t seem to be in pain. She is over weight (I have her on a diet) so maybe it’s from that but I never took notice to it before.

  2. Avatar Of Pat Ammons

    Pat Ammons


    My jack Russell has a lump between her ears at base of skull about size of a pea under skin not visible no hair loss seems fine the hair is natural over it what can this be

  3. Avatar Of Deborah Flynn

    Deborah Flynn


    I have 2 shitzu’s they both get cyst on them the vet took them off the oldest one but they keep coming back what can we do

  4. Avatar Of Nancy Smallwood

    Nancy Smallwood


    In 2016 I had a 5yr old ship tzu named JP!He was My Everything to me!!I got him at 6 wks old.Not knowing anything about dogs & cancer!Well,thru the years,JP was a normal dog!I did notice that his belly always looked bloated!I didn't think anything about it!!I just thought it was from him eating & eating!Well,the yrs kept going on!JP got to age 4,I started noticing a hard Like thing petrifying from under JP's skin around what I thought was his stomach!It kept getting bigger &a bigger!So,I took Him to the vet.She examined him.And,said the JP had a enlarged Spleen,&a he needed a Ultrasound!JP got one.And,in Oct,2016 the vet told me that JP had Lymphoma in his spleen & liver!!There wasn't anything they could do but for me to take him home & make him comfortable!We couldn't tell that JP had any kind of cancer!Because,JP was a spunky l'il dog!He didn't show any pain or nothing!!I asked the vet ,when will I know when I will know when to put him down so he wouldn't suffer!!They gave me a list of stages that JP would go thru!!JP didn't show any signs of cancer until the end of Feb,15,2017!He turned 6yrs old!He really started showing the signs on the list the vet gave me really quick!!My Little Baby Boy Was On Death Row To Me,Waiting To Die!!So The Reason Im Telling JP's & My Story Is Because,If I Can Help Another Person's Loved One!!Then JP Didn't Die In Vain!!So,If U Feel Or See A Bump Or Mass!!Get To Ur Vet!!I found out that there r 4 or 5 kinds of cancer's that Ur dog can get!!JP Fought Til The End!!He Didn't Want To Leave His Mommy!!But,The Last Symtom Was Panting Constantly & Trying To Get Comfortable & couldnt!!I Sent My 4-Legged Fury Baby To Doggie Heaven On 4/15/2017!I had Him Creamated!His Spirit Will Always Be With Me!!And,The Knowledge Of Canine Cancer Will Always Be Etched In My Mind!!Signcerely::Mother Of My 4-Legged Furry Baby JP!!

    • Avatar Of So Mezher

      So mezher


      I’m so sorry. I’m crying right now. I love my dogs like that too. I’m so sorry. But I’m sure his spirit sits next to u

  5. Avatar Of Cl



    My chiahuahua has had a lump on her neck close to her shoulder blade for a year. it started growing slowly.
    A very small one developed on her right shoulder several months ago and now it growing.
    Last night, I noticed one that just popped up in her mammary gland and one on her back near her spine.
    She is almost 8yrs old & hasn't been spayed. I think we may need to spay now.

  6. Avatar Of Sally



    My dog is a whippet x and she has a few lumps on her body but my main concern is her tail it’s so lumpy bumpy is that normal for a dog of 12 and a half years old

  7. Avatar Of Lisa Thomas

    Lisa Thomas


    Please help,My 14yr old poodle has lumps all over her belly underneath her tits and they have gotten bigger and sore to touch,I do not have the funds to take her to vet and have a bunch of test done please give yr opinion on if u think it may be cancerous

  8. Avatar Of Ray



    My pomerian dog have a lump on her belly what should I do.

  9. Avatar Of Barbara



    My dog has been getting a cyst like bump right at the top of her tail and top of her back , we have continued to pop it clean it thoroughly with much relief to her but they seem to keep coming back in the same area. She shows no signs of illnesses or pain but it I’d rather pop it and not have it there. Does this just sound like a reoccurring pimple type?

    • Avatar Of Nancy Smallwood

      Nancy Smallwood


      Hi Barbara,My shih tzu had a big lump where I thought it was his stomach but it turned out to be his spleen!And,to my horror!!He had lymphoma cancer!Also,I didn't get it checked out Til it was to late!JP passed away because his spleen & liver was full of cancer!!My Advise To All Pet Owners Is To Get Things Like This Checked By A Vet!! I am not a vet!So I can't tell u what ur pet has!!I can just tell u what I've learned by my Pets demise!

    • Avatar Of Hailey S

      Hailey S


      Hi love,
      My dog who was a Lab/Collie cross had the exact same thing. I'm trying to figure out what kind of cancer she had so that I can get peace of mind, but hers swole up so large and her tail was necrotic underneat the fur and literally fell off, and the tumor on her tail/lower back area popped. I'm still horrified today after finding my baby with no tail and in so much pain, but I hope this helped and you get your dog checked out. She was about 10 years old, so we knew she would be leaving us to cross the rainbow bridge, but definitely did not expect cancer.

    • Avatar Of Nancy



      Hey Barbara did you take your baby to the vet about that fatty deposit you found at the base of his/her tail

  10. Avatar Of Doris Crabtree

    Doris Crabtree


    My 16 year old Chihuahua has a lump that has dropped down tonight.there was 2 now they dropped down and there is a large one. Its under her at her end almost between her legs.
    Please help

  11. Avatar Of María Rivas

    María Rivas


    I notice lump on My malteses dog irritaded and painfull
    Lucía its her name im worry shee its My lífe but My económica situación its Not that great Please let me know If its any please that can help me a low Cost

  12. Avatar Of Amy Mcinerney

    Amy mcinerney


    My 9 week old chihuahua puppy has a small lump on her belly and feels like it may have PUSS! I’m scared for her please tell me what I should do or if it should be a concern..its not hot red or irritated it’s just a lump smaller than a dime and may have puss

  13. Avatar Of Mindy Mindy says:

    I noticed I lump on my dogs head right over her right eye .. It’s the size of grape and it’s under the skin it’s not red it doesn’t bother her there’s no puss are opening or anything .. Sometimes it’s gets bigger and her eye starts to close A little bit and then the next day it’s completely gone I may be a couple days later . Does anybody have any idea what it could be

  14. Avatar Of Letha



    My 2 year old lab mix has a lump on the underside of her tail and I am concerned. Shes otherwise very healthy, active, and the lump doesn’t seem to bother her and hasn’t changed in size but I am concerned. I am worried the Vet may want to surgically remove it but I am very limited financially and couldn’t afford surgery right now. I am torn because I love my dog and want whats best for her. Any financial advice is appreciated.

  15. Avatar Of Letha



    My dog is a lab mix who has a lump on the underside of her tail. It hasn’t changed in size and doesn’t seem to bother her but I’d like to get it checked out by the vet but I’m worried they may have to remove it surgically and I am very limited financially and I can’t afford any surgical procedures for my dog but I love her so much and want whats best for her. Any suggestions for financial help?

  16. Avatar Of Cathy



    I have a 9 year old daushund and we have carry her to 3 veta.with bumps all over back and her feet.And they have put her on 3 driffent mads.She gets them other year about this time of the year.Please tell me what I can do for her she scahing them.Is there anything I can wash her w th her with,the meds are not helping.

    • Avatar Of Janf



      As a dog groomer I see this on and off. It usually comes at the time of year when things are growing so I think it may be a form of allergy.
      In our salon we use a medicated shampoo with Tar & sulfur. This helps but does not eliminate the bumps.
      If your area has a Dermatology Veterinary service I would seek them out. They have access to medication that most Veterinary offices do not have.

  17. Avatar Of Rachel



    Hi. I have a 9 year old half dachshund half Chihuahua female dog. And she got an odd looking bump about where her heart is. The bump is weird shaped and looks like it has a bunch of little bumps in it. It is also on top of the skin. I don’t know this this is cancer or if I’m just freaking out over nothing. Does anyone know what this is?

  18. Avatar Of Louise



    My dog had a lump located close to the end of her tail removed on June 19 2019. There was a miscommuication between the vet and myself. I never got to speak to the surgeon who removed the lump. I thought the small lump would be removed only if it was cancerous. They removed it without knowing if it was cancerous until after the fact when I requested a lab report. The report came back as non malignet tumor. The problem I am now having is after the stiches were removed she pulled the bandage off and chewed some of her tail. It bleeds and I went to a different vet and they said it is going to be very difficult for this to heal and they want to dock her tail. This has been a nightmare since her tail used to curl and was so much her personality. Do you have any words of wisdom that will help. I plan to try and keep what tail she has after the surgery. They took about a couple inches off. Thank you for your help in this matter.

  19. Avatar Of Jamie Geer Jamie Geer says:

    This was interesting, I wish however that it told more about distinguishing between lumps, bumps, cysts, and swelling. I have one dog that is prone to benign cysts that we regularly have removed simply because we don’t like them and want to be able to distinguish old from new, but another one of our dogs suddenly was noticed to have swelling under her chin. Thankfully, we promptly took her to the vet to have it checked out because it turned out to be lymphoma (you can see her story at savebambi.net or her Facebook page facebook.com/pages/Save-Bambi/616673938402311) We have been doing everything we can to save her and she is currently in remission and we are desperately trying to raise the money to pay for her transplant that could not just extend, but save her life. If we had waited she may not even be alive now because this lymphoma left untreated most often kills within six weeks. People need to be aware of where their dogs lymph nodes are located and what they feel like so that that they can closely monitor their dogs and as soon as they notice a change get their dog to a vet, if their vet can’t get them in within one to two days they need to try another vet that can.

  20. Avatar Of Erin



    Hi my name is erin,
    Im wondering what the lumps are under my teacup chihuahuas belly,
    near her lower nipples are located. One is located near/under one nipple,
    and another (smaller) located near/under another. They are also soft.
    would u happen to know what this could be?

    • Avatar Of Jodie



      Hi Erin, our little girl has just developed the same problem. What did yours end up being?

    • Avatar Of Ronnie



      I had a similar situation with my Maltese. The “bump” was removed along with her mammary gland. It turned out to be a low grade breast cancer. Hence, the mastectomy. Have your dog checked immediately by her vet to be safe. There should never be a delay in examining bumps in the breast area. Since she had surgery early, my vet feels my pup will be fine. Good luck.

  21. Last comment was for PETA Scott not Sheila B.

  22. Sheila B. did you happen to notice when your dog was drinking those huge amounts of water if he was vomiting up a foamy clear liquid? We had just gone through this for several months this summer. Our dog had high count of protein in her urine. She’s 8 yrs. old, a Maltese weighed 18lbs. Over weight. We watch her diet now. And she’s on Hills UD for her chronic urinary infections that started this summer. We have to use special wipes for her. We always wiped her, but these are anti fungal/antibacterial. So I suggest you take your dog to the vet SAP Uti’s are painful and can turn into serious stuff. Our dog also had struvite stones removed, I failed to mention when this all went down. Best of luck. Hope this helps you. We love our pets. Cheryl

  23. Avatar Of Peta Scott

    PETA Scott


    Hi can anyone please help me with my 15yo kelpie male that has some huge cysts that the vet assures me are harmless unless they affect his joints. He has started coughing up huge amounts of liquid at night I thought it was urine but its not, it would be Atleast a litre, he does it in his bedding or anywhere, as for his general health he seems happy he even plays sometimes with our other dog.i know he’s old and I expect him to have accidents but I just wish I knew what this is, he drinks a lot of water and we always let him out before bed, but once again it’s not urine. Thanks for listening PETA

  24. Avatar Of Nicole



    i have a dog that is 11 years old and i just noticed a lump under her skin its not real big it looks like a bead is under her skin its just above her nipple closer to her front leg wat could it be and would it need to be removed she is a little maltese dog plese help im worried

    • Avatar Of Sheila B

      Sheila B


      I just noticed your question when I was looking for information for my son. He has a dog with cyst on his tail. Anyway, I have had a few Maltese, I have one right now. She is 15 and gets these small to medium size growths on her. I have had her at two vets and they have both told me that these growths are very common in the Maltese breed, especially when they get older. I make sure to keep her skin clean and hydrated and watch the growths for any infection. They seem to come and go and can sometimes bleed. I put a salve on them that I got from a pet catalog and the vet says that’s about all I can I do. They do seem to be better when I bath her with a good hypoallergenic shampoo. Good luck! I love this breed of dog.

  25. Avatar Of Brandy Arnold

    Brandy Arnold


    My dog, Molly, a few years ago developed a small, squishy mass on the underside of the base of her tail. My veterinarian drained and tested its contents and deemed the cyst to be harmless – her body’s reaction to a bug bite, probably, as long as it remained small and didn’t get in the way of her normal activities. Because she is a long-haired dog and the cyst was under her tail, it wasn’t really noticeable – much to my dismay. When I checked the cyst about a month after draining it, it had doubled it’s previous size.

    Molly and I began a regular routine of draining, waiting for it to fill up again, draining again, and so on… until we reached the point that in under a week it was full again. And each time it refilled, it became larger and larger. Well, you may be wondering why I went to all this trouble rather than just having the cyst removed permanently. Because of the location of her cyst, my veterinarian was concerned about operating in an area rich with nerves that might effect her bowel control. He even suggested removing her tail altogether – a notion that I couldn’t even fathom as watching her tail windmill when she’s excited is one of my favorite pastimes.

    In one of the best decisions I’ve ever made, I decided to take Molly to a highly regarded vet for a second opinion. I suspect Molly’s original veterinarian was just too busy to be bothered with a complicated surgery on an older dog because my new vet, after 6 hours of intensive surgery, successfully removed the cyst – and only the cyst – relieving Molly of the years of carrying around a sac that, at one point, weighed nearly a pound and contained a full liter of clear fluid. My suggestion for anyone that finds a lump of bump on their dog, is to get a first opinion – and then get a second.

    • Avatar Of Jane Russell Songer

      Jane Russell Songer


      Oh, my goodness! Thank you for sharing that! That is horrible that you & your precious dog had to go thru all that! I salute you for getting a 2nd opinion! I can’t get OVER that the cyst was so HUGE! A LITER: OMG!

    • Avatar Of Peta Scott

      PETA Scott


      Hi my old kelpie who is 15 has huge cysts in and on him and he has started I think? Vomiting huge amounts of liquid (1 litre clear) at night in his bed, or anywhere in the house. I thought it was urine but its definately not, can anyone tell me what is happening. The vet says the cysts are no need for worry, and as far as I can tell he still has his usual ones on him that he’s always had. Peta

    • Avatar Of Laura



      I’m really glad to hear this was a harmless bump. I have found a couple of small bumps on my dogs back that my vet said were most likely benign cysts. Reading that your dog is alright makes me feel so much more relieved about my little girl.
      Thanks a lot for sharing! I’m happy that Molly is back to being her normal, tail-wagging self! Cheers! 🙂

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