Help! My Dog Has A Lump

‘At A Glance (Details Below)’ What to do

When A Dog Has A Lump

  1. Get new lumps checked regularly to ensure they are not cancerous
  2. Most lumps are benign and can be diagnosed on the spot at the vet
  3. Successful removal on the head, tail and legs requires earlier surgery

Now dive deeper…

If you’re a dog owner, it’s almost inevitable that you’ll find a lump at some point. Dogs get lots of lumps and bumps, especially as they get older. How do you tell which ones are more serious?

Believe me, it matters. You don’t want to know how often we see a lump that could have been removed if only the urgency had been recognised. The trick is to know the warning signs of dangerous lumps on dogs.

Which Dog Lumps Need Removal?

Some of the ways you can identify a dangerous lump are:

  1. Speed: if a lump looks bigger in only a month it’s growing rapidly
  2. Shape: smooth, round lumps whether on or under the skin are usually worse
  3. Appearance: black, pink or ulcerated surfaces are more worrying
  4. Feel: subcutaneous lumps should move easily between the skin and the body
  5. Position: watch out for lumps on the head, legs and tail (I’ll explain later)
dog skin tumour
Typical appearance of many skin lumps such as mast cell tumours or histiocytomas. Slide shows typical FNA appearance

Later I’ll show you the most common lumps we see. However, the only way to know for sure is to take a biopsy. That’s where we take a small piece and get it examined. A biopsy does two important things:

  1. It tells us whether the lump is dangerous or not
  2. It helps us decide how big a surgical margin we need

Common Lumps Of Dogs

So the earlier we see a lump, the more options we have. If you’re afraid of bad news, don’t be; despite the horror stories, a biopsy or surgery isn’t always needed, and most lumps are benign. Your vet can even identify most lumps straight away. Here’s what they are and how we can tell.

See also: Common Mouth Lumps Of Dogs

Lipoma or Fatty Growth

What they are: the classic lump under the skin of older dogs. It’s actually a benign tumour of fat cells, and should grow so slowly it takes 6 months to see any change. Most often found on the chest or abdomen.

How we tell: a fine needle aspiration (FNA) like I’m demonstrating in the video gives a clear answer. Never assume a lump is a lipoma unless your vet has done this first.

Treatment: none, usually. Lipomas need removal only when they occur in difficult positions like the legs or armpits. I also take them off younger dogs if they will get huge in a normal lifespan.

Soft Tissue Sarcoma

dog sarcoma tumour

What they are: fast-growing, locally invasive tumours of connective tissue, common in large breeds.

How we tell: biopsy is necessary. Sarcomas feel just like lipomas and are often mistaken for these if a needle aspirate isn’t done. A clue in this case is the position; lipomas are rarely on the legs.

Treatment: prompt, careful resection with a wide margin. The picture shows a fibrosarcoma on a leg with a standard 2cm margin. I hope you can see why the earlier we check these lumps, the better.

Sebaceous Cyst

What they are: a blocked sebaceous gland causes a buildup of hard, cystic material under the skin. Often found on the skin along the spine or neck.

How we tell: a fine needle aspiration gives a clear answer.

Treatment: none, usually. Most sebaceous cysts never cause problems.

Sebaceous Adenoma

sebaceous adenoma dogWhat they are: a benign tumour of sebaceous glands, often wrongly called a wart. Very common in Poodles, Maltese, Bichons and their crosses. This one is on an ear.

How we tell: biopsy is necessary, however, the classic appearance and slow growth make us near-certain just by looking.

Treatment: most sebaceous adenomas never cause problems, but any that are ulcerated or being licked need removal.

Skin Tag or Wart

canine papilloma

What they are: multiple small lumps often on the face and head. Just like in humans, warts are caused by a papillomavirus; dogs that get them go to dog parks or day care.

How we tell: biopsy is necessary, however, their classic feathery appearance is hard to mistake.

Treatment: none. Although they can look terrible, warts should go away by themselves after a few months.

Mast Cell Tumour

What they are: fast-growing, pink button-like lumps which can be well-behaved or very aggressive. MCTs have a reputation for recurring following incomplete removal.

How we tell: your vet can usually do it via fine needle aspiration (see earlier) but sometimes a biopsy is required.

Treatment: should always be removed with a margin depending on the ‘grade’ or severity.

dog nasal infectionGranuloma

What they are: fast-growing, raised red lumps sometimes with a surface crust. Granulomas look like aggressive tumours but are actually a solid form of bacterial infection.

How we tell: sometimes a biopsy is required but we are often sure enough just from inspection.

Treatment: antibiotics, not surgery.


canine cutaneous melanoma
What they are: slow-growing, dark lumps not caused by sunlight. Skin melanomas of dogs need removal, but they are a lot less malignant than human ones and shouldn’t make you lose sleep.

How we tell: there isn’t much else that’s black.

Treatment: removal. Baxter (pictured) gets repeated melanomas. After removing the first few we have been watching his latest set for signs of growth.

Haemangioma and Squamous Cell Carcinoma

dog haemangioma lump
What they are
: two tumours caused by ultraviolet damage from sun exposure, common in Adelaide on unpigmented areas of sunbathing dogs. You can see that the one on the dog’s leg has started on a pink area.

How we tell: haemangiomas are red, berry-like masses that bleed easily; squamous cell carcinomas are raised, crusty sores.

Treatment: removal. SCC, in particular, can spread to lymph nodes and cause death if left too long.

Follicular Cysts

dog follicular cystsFollicular cysts are rare skin lumps caused by dilation and rupture of hair follicles. Although they may look like tumours, they are benign and usually easy to remove.

A Mystery Lump

floppy benign lumpThis one we also see frequently. It’s very soft and squishy, has an irregular outline and is extremely slow growing. I have never needed to have one removed or tested.

Phew! There are lots of rarer lumps on and under the skin but I hope you’ll never see them. For example, the other one at the start is a Sertoli Cell Tumour caused by a retained testicle. No dog should suffer from any of even the worst of these tumours if you get them checked in time.

dog cutaneous lymphoma
Epitheliotropic lymphoma

Even rarer is the last one. You can read more about epitheliotropic lymphoma here.

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 Facebook 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.

Note: comments below are welcome but please remember that only a visit to a vet can truly tell the identity and seriousness of a lump.


51 Replies to “Help! My Dog Has A Lump”

  1. Hi! I am on vacation right now and not near my vet. I’m very familiar with all of the lumps on my dog. This morning I noticed what looked like either a skin tag or a tick on my dogs leg. I don’t see any legs on it like if it were a tick but she did go walking in a little woods between camp sites. I played with it enough trying to check for legs and a little oil came out of it. After the oil came out, it seems the skin slid back and now it looks like a pink skin tag. I have pictures but cannot seem to add them here. Please help!

    1. Hi Erika. Sorry you can’t send pictures but they are very hard to get a definitive answer from. It’s very unlikely to be a tick because (with good eyesight) you can see the tiny little legs at the end where it attaches to the skin. Most of the time in this situation it is a skin tag or another sort of lump instead. If you don’t live in a paralysis tick area (east coast of Australia) then it’s not an emergency but of course a visit to the vet is recommended.

  2. i cannot find info online about this–I am saving up for a vet visit in 2 weeks. I have an 11 year old white chi/pug. I noticed one small white bump in the middle of his tail with hair loss a few months ago, but didn’t worry too much about it. It didnt seem to bother him. Now there are 10 of them in a cluster, and more hair loss in the area the bumps are. I am worried that there is no easily found information about this spot or pictures similar to how this looks. Any ideas? Thank you.

  3. My 10 year old boston terrier has a very hard non movable lump on his back below his shoulder blades. He has two lipomas but this is much firmer. I’m going to get it checked out but it has me worried. Is it possible that this could be a lipoma too? It’s round.

    1. Hi Andrea. Lipomas can fool us sometimes, but this doesn’t sound like one, especially because it’s firm and non-mobile. Getting it checked out is definitely the best thing to do.

  4. my dog has a small oval grey mixed with black thing under her armpit it looks like a bean sprouting under arm and i don’t knwo what it is and i’m scared

  5. Hi my 6 year old Doberman develop a wart-like lump on her right side chest area, where her right front leg can rub on when she runs. First noticed it about 8-9 months ago, it was very small back then. But now 8 months later it has doubled in size, I measured today at 0.8cm. It light pink in color with some black pigmentation, soft like a nipple (in fact at first I thought it was another nipple!). She doesn’t seem to be bothered by it and it do not bleed or oozes. Her vet doesn’t seem to be too concern about it because she say she can basically pick it up together with the skin and couldn’t feel it attach to anything underneath her skin. So it’s basically just an above the skin lump.

    Do you think it looks worrying? Does double in size in 8 months time consider fast growing? It grows about 0.05cm-0.1cm every 1-2 months, not really noticeable with the growth by eye but I keep a measurement almost monthly.

    1. Hi Kerry. Your vet is right in saying there is probably no urgency in dealing with the lump. That’s because very few skin lumps in dogs will metastasise to elsewhere in the body and this one has a wide margin of skin that can be removed with it. If the local growth is acceptably slow (as it is) then it’s fine to watch them.
      However, in your case I would have this lump removed. The lump does not sound like anything simple, and given that your Doberman is only six years old, you can extrapolate that it will become a problem in time. Although it’s just my opinion, I would rather take this one out while it’s small and possibly also get it analysed just in case another one appears.

  6. Hi, my 8 year old poodle mix has had a lump on his hind leg for about a year & a half. When it first appeared, it was a little smaller than a pencil eraser. We had it checked out, and vet simply told us it did not look serious and to keep an eye on it. Now, it has grown slightly bigger than pea size. It is round, a little squishy, and can be moved around. Slightly pink. My dog never seems to notice it. Now, the vet still doesn’t believe it’s serious but wants to remove it while he cleans my dog’s teeth “just in case.” I am going to another vet to request a fine needle aspiration because I’m worried about MCT. Does this sound anything like a MCT?

    1. Hi Amee. It’s hard to be sure, but it sounds a lot like the mystery lamp I’ve described above. The path your vet is suggesting is a common and very sensible one, in removing a lump under another simple procedure just in case it’s a problem. I also like your thinking and getting an FNA first because it’s very hard to ever be certain about a lump without one. However, in your case I think it’s safe enough to trust your vet’s judgement that it’s not an MCT.

      1. Thank you for the response. I did have the FNA done & vet was unable to give me a diagnosis because she got mostly skin cells in the needle. I am having to the bump removed while my dog is having his teeth cleaned in a few weeks. The vet has given me the option to send the bump off for biopsy after getting it removed. Is it worth it? If not cancerous, what else could the bump be? The vet who did the FNA was pretty certain it wasn’t a lipoma or MCT, as she says those probably would’ve shown up with the FNA test. This whole bump situation is driving me nuts.

        1. Hi Amee- good to hear, and yes, FNAs can be unreliable. You can trust your vet’s opinion on whether the lump needs analysis. I would approach the issue by cutting it open after removal and unless it’s an obvious cyst, I would always advise sending it. The only drawback is the $200. Many owners decline this, and that’s perfectly OK too, especially if the vet says they got a good margin around it.

  7. I’m not sure if this is something to worry about. It feels like a boil on the inside of my boxer/pit hind right leg.

    1. Whether it’s important will depend a lot on the age of your dog, the lump’s size and how quickly it has grown. However, it’s probably worth getting checked all the same.

  8. Hi,
    My 7 year old golden retriever has a good size mass/lump near the top of her tail (about 2 inches down from her anus on the right side). It is hard, doesn’t feel squishy at all. The area around it is red & the lump itself has shades of pink/red/black/blue and its very slightly crusty at the top. I can tell it goes way beneath the surface of the skin. She doesn’t seem to mind when I touch it. Thoughts?

      1. My 1 and a half year old mastiff lab mix has had a round bump on the top of her snout since about 6 months old, it happened around the time she received her rabies vaccination, in the same placement as the picture of the mast cell, although it is fur/ regular skin colour, it does not seem to bother her much, no breathing issues, or any mucus. I have brought it up the the vet twice now, and they are not seeming to be concerned. I am however a little concerned as it has seemed to be very slowly getting bigger, however slow growing this thing is, it is about the size of a golf ball or a little smaller. What would be your recommendation? It looks like the picture of the lumps on the leg of the dog with the soft tissue sarcoma. It was almost like all of a sudden it happened, we originally thought it to be a bug bite of some sort but it never seemed to die down or go away! It is firm to the touch, but not hard per say, it is not malleable under the skin, no pain upon putting pressure on the bump Thankyou in advance ! I wish I could post a picture of this thing haha

        1. Hi Emma – anything the size of a golf ball sounds like something worth taking seriously. I would do like I said in the article and get a fine needle aspiration of the mass. It’s very easy, and will tell if more should be done. It’s very hard to say what it could be in such a young dog, but a tumour would seem unlikely.

  9. We have a nine year old Golden Doodle. Riley has always had from a very young age, lipomas over his chest and sides. They grow slowly and we have had them checked (FNA) by our vet. Recently we got back from a trip and noticed a large lump that popped out on Riley’s left hip, very large and felt like it had sections. It was soft but firm. A needle inserted brought up blood so my vet assumed it was an abcess. After the first needle drainage, it required additional work which had to be done under anesthesia. He had multiple drains, antibiotics and finally another surgery to open the small incisions. A biopsy was sent twice and the verdict seems to be soft tissue sarcoma. Once the drains and the stitches were out, the skin healed very quickly but the lump/bumps are now three times larger, very firm and although no x rays or MRIs have been done, we are being told it is invasive soft tissue sarcomas and is probably in his bones. Riley is walking easily and asks for his daily walks every day, but he is breathing heavily after a gentle mile and a half. Should we have him put down before he exhibits pain, should we put him through more tests? Right now he sleeps most of the day, occasionally plays, runs, jumps, barks, rolls, and generally appears well. The lumps do not seem to hurt him although they look very bad. He eats very well, begs for treats, has no trouble with eliminations.
    Occasionally he drags his left hind leg or appears to stumble but exhibits no other discomfort. I am unsure if we can or should do more to find out how extensive the cancer is and if he is just not letting us know how much it affects him. Any advice would be welcome. Kim and Vic

    1. Hi to you both. Your story demonstrates the ease with which sarcomas are missed, especially in dogs that have a history of lipomas, which look very similar. Although I have seen it happen a few times, sarcomas actually rarely spread to the bones, and cause most of their harm by local invasion. One of my patients with a similar tumour recently lived for 12 good months after diagnosis. I believe it’s always important to judge the time for euthanasia by their happiness and quality of life, not the appearance of the mass. A good idea in the meantime is to trial some pain medication to see if it helps him.

  10. Hi I have a 2 year old Jack Rusell called Foxy and have noticed today she has a small hard lump on the lower underside of her tail. I have put pressure on it to see if she has any pain as it is very hard but she doesn’t seem to feel anything…. Should I get it checked by a vet as I am a bit worried.?

    1. Hi Dougie. If the lump is < 2mm in size and not growing it's almost certain that your vet will tell you to keep an eye on it. Any bigger and I'd get it checked as lumps get hard to remove on tails very quickly.

  11. Hi,

    I have a 9 year old pit mix terrier mix that recently had surgery to remove benign mammary masses. Her surgery was successful. She had a lump on her tail for quite some time and now since surgery its been growing very large and quickly. What could that be?

    1. Hi Sam. All I can say is that it should not be related to the previous surgery. The most common lump on the tail is the Perianal adenoma which usually (as the name suggests) is found around the anus, but can also be found on the base of the tail. These are benign but still need removal before they get too big. Of course, any of the lumps mentioned above can also be found on the tail too.

  12. I have a 8 yr old female Yorkie. She has a small raised lump (smaller than a pencil eraser) right in front of her ear close to the top of her head. It is pink with brown areas. It almost looks like the brown areas are growing on the pink lump. I am concerned about the discoloration. She gets regular massages, so I know the lump is new. Please advise.
    Thank you,

    1. Hi Jamie. It sounds like a sebaceous adenoma (see above). One clue is that you should be able to easily scrape off the brown areas with your fingernail.

      1. Thank you Andrew. The brown area will not scrape off. It does have some characteristics of the sebaceous adenoma, but the pink area looks waxy. It also looks like tiny red blood vessels in the pink bumpy part.

        1. Thanks. It’s not easy to give another suggestion so it’s best to get a vet to take a look. Once you do, please let me know the outcome.

  13. I have a 3 yr old Min Pin who just went through her second heat cycle a few weeks ago and I just noticed on her very lower belly on one side, she has a lump. It’s not hard and it kind of feels like liquid. What could this be And is it serious?

    1. Hi Kerrie- it’s probably a cyst in the mammary glands based on her recent season (she could even have a pseudopregnancy- squeeze a nipple and see if there’s milk). If so, nothing to worry about but of course, standard disclaimer… only a checkup will confirm this!

      1. Thank you so much. This is my baby and I was really starting to worry. This eases me a little. I’ll definitely get her checked out.

  14. Hi! We have a 1.5 year old plott hound and first noticed a small red lump on his head in early February. It grew larger and crusted over. Our vet said it is a Histiocytoma, which is benign and usually goes away on its own. However, the growth has opened and it is a bit raw and red now with some crust around the edges still. Our vet recommended putting him out to remove it, but we’re unsure if we should if it is just going to go away on its own? Any help you can give is appreciated! I have a photo but am unsure how to attach it here

    1. Hi Brianna. It doesn’t sound like a histiocytoma now that it has broken open so the advice you received is probably correct. The only other thing I would wonder is whether it might be a granuloma (there’s a picture of one on a nose at the start of this page) I don’t think a photo would help all that much as we are often in the dark over exactly what these things are. Certainly, not all of them need removal but after a period of time (especially on the head without much skin) it’s a good idea to have it removed.

  15. Hello, I have read all of your content (as far as I can tell) regarding various lumps our furry children are subject to and I am fairly certain the Iumps my german shepard (Archer) has, look just like Sebaceous Adenoma but have a flakey surface layer like a Granuloma or a Planters Wart. So I am still unsure of a course of action.
    I know the info you provide isn’t intended to replace a visit to the vet. It’s just that Archer and I are not at all financially stable, another way of saying it is that we are broke as hell and can’t afford any sort of medical bills at the moment. I would be eternally grateful for any help what so ever. Like if I were able to send you a few hd pics of Archer’s lumps. There are two spots which are located just above his hips ( hopefully that is relevant info) thank you in advance for for your time and dedication to this field of work.

    1. Hi Drake- you are welcome to send the photos via our website email. Just sent an enquiry and we will respond to you with the address. If the images have adequate detail and lighting I will add them with a comment on this page. (worth a look as sebaceous adenomas aren’t common in big dogs)

  16. Hi Andrew!
    I have a husky-mixed mongrel and he is around 10 months old. I’ve just found a 5cmx 5cm mobile lump under his fur around his belly area. It is completely covered by his fur, the lump is soft , mobile and not painful. He is otherwise eating well.
    I’ve booked a vet appointment already but just wondering what could it be.

    1. Hi Winnie. It sounds like an umbilical hernia, but if so it would have always been there (possible in a hairy puppy). These are right over the ‘belly button’ area. Definitely worth a check though- let me know the result.

  17. I have a 12 yo mix (I think he has some Pit and maybe some Dane in him). He is about 80lbs. For about a year he has had a soft round lump under this skin on his chest that is not tender and is completely covered with his fur ( so no hair loss). You can kind of move the lump around and it does not seem to bother him. I can’t afford a Vet due to just losing my last one to Mast Cell Cancer and being in debt from that. She was 13 so I am scared. He also has a dark brown bulbous type growth that almost looks like an extra paw pad but it looks like it is very slowly getting bigger. It is outside l, clearly defined and smooth. Doesn’t seem to bother him and is about an inch round (if that makes sense – so like an inch across and an inch length) no pink or anything. Just looks like a large extra paw pad that has very slowly gotten bigger. Any thoughts?

    1. Hi Rikki. The first lump you describe sounds like a lipoma, which is a typically benign fatty tumour under the skin of dogs. It should be mobile, rubbery, and very slow-growing. These are usually okay to watch unless they occupy a position that interferes with mobility.
      The second lump I’m sorry I could not identify from the description.
      Can I stress for both lumps the low cost and importance of getting a vet to check them while they still can be taken out. For example, a mast cell tumour identified via a fine needle aspiration when less than a centimetre in size is almost always removable. In our clinic the cost for such a check is only a consultation fee at around $60.

  18. Hi there I’m worried about a pea size lump my chihuahua has on her back it is under the skin and doesn’t appear to have any color she seems fine in herself do you think that it is anything to worry about.

    1. Hi Lauraine. It depends how fast it is growing, and what it is. I would get a vet to do a fine needle aspiration to check if it’s a cyst (not much to worry about) or a tumour. However, even if it’s a tumour, if it has been there for a year or more without change it’s probably OK.

  19. We have a boxer about 7 years old and has a black bubble that looks like melanoma on the side of his eye. What would you suggest to do?

    1. Hi Louisa – Boxers are very prone to tumours and black pigmentation is suspicious for melanoma. It’s certainly worth getting your vet to have a look.

  20. Hi my Nancy is Chris. My 3 yr old English Staffy has a smooth round lump on the under side of her tail that trails off. I have seen a vet who was supposed to do a biopsy but didn’t get time. However after reading your article I am thinking maybe be best to take the whole tail as it is cartilage and ankored to the bone ? What do you think? It’s close to the base of her tail.

    1. Hi Chris – you are right in saying that it is often necessary to remove part of the tail with nasty lumps in that region. However, there are certainly benign growths that don’t require this so a surgical biopsy is wise first.

  21. I’m in need of help with my hairless pit bull!! He got this thick round growth around his penis and I took him to the vet payed $350 and they didn’t do anything but prescribe steroids and it didn’t help. I think it made it worse. Now it spread to his penis head and it looks horrible and I don’t know what to do. I can’t afford taking to the vet anymore and it’s just not getting any better. Can someone please help me !!

    1. Hi Silvia. I’m sorry that there is no easy alternative to getting lumps like that biopsied if they don’t respond to treatment.

  22. We have a 5 month old weimariner. We just noticed a large lump on the top of her head. It is soft ro the touch and doesnt seem to be slowinh her down any. She still eats and plays, but this has developed in the last day or two. Any thoughts? I plan to take her to the vet tomorrow, if at all possible.

    1. Hi Alice. It’s hard to say without seeing it but if the lump is soft and centred exactly over the bony prominence on the top of the skull it may be a seroma caused by impact. I’m only guessing this because you have a five month Weimaraner, just the sort of breed to go knocking their head on the underside of tables! Definitely get it checked though.

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