Petco Text Logo
Petco Pet Logo

What's this red lump on my dog's leg? Is it a tumor? When to see vet?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Male | neutered | 5 years and 3 months old | 55 lbs

My dog has a red lump on his left leg

5 Answers

Most Helpful Answer

Image profile

Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

Veterinarian

Published on December 19th, 2021

Hi again and thanks for sending the pic to us. In this case this lump seems to be a tumor and would need ideally to be checked by your local veterinarian to differentiate in between benign and more sinister ones. The lump seems big enough to be able to take a fine needle aspirate from it without using local or general anesthetic. A small needle can be inserted inside the lump to get some cells out and analyse them.

Vote icon

1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Image profile

    Answered By Dr. Massimo Orioles, DVM, Cert AVP, MRCVS

    Veterinarian

    Published on

    Hi and thanks for your request. In this case a picture of the lump would be essential to determine the underlying nature of it more specifically. I would recommend to send it by email to our customer care service.

    Vote icon

    0Pet Parents found this answer helpful

  • Image profile

    Answered By David Elbeze, DVM, MRCVS

    Veterinarian

    Published on January 1st, 2017

    This lump needs to be checked and analysed as there are many conditions and types of tumors that could look like that. take Charlie to the vet, they will perform a fine needle aspiration on the growth and send it to the lab for analysis. when the result comes, the vet will advise what needs to be done according to the diagnosis.

    Vote icon

    1Pet Parents found this answer helpful

  • Image profile

    Answered By Andrea M. Brodie, DVM

    Veterinarian

    Published on October 9th, 2018

    Unfortunately the photos are not very sharp when I try to enlarge them. The fact that this mass is growing is a little concerning. This may be a little abscess, cyst or tumor. You should have it examined by your veterinarian as a tumor should be removed ASAP, especially on the leg, as there is not so much skin available to close the incision after removal. An abscess can usually be treated with antibiotics and/or be lanced, and a cyst can be evacuated. Your vet may want to do a fine needle aspirate (he takes some material from the bump with a needle and then looks at it under the microscope) to determine whether the mass is concerning.

    Vote icon

    1Pet Parents found this answer helpful

  • Image profile

    Answered By Jennifer Summerfield, DVM CPDT-KA

    Veterinarian, Certified Dog Trainer

    Published on November 20th, 2016

    Without seeing the lump, it's hard to say what it might be. Some possibilities would include a localized bacterial or fungal infection, a local inflammatory reaction due to an insect bite or sting, a lick granuloma (causing by excessive licking), or even a skin tumor of some kind. I would recommend having the lump examined by a vet when you are able to - he/she can do some testing if needed to help determine what it is and what treatment is needed.

    Vote icon

    1Pet Parents found this answer helpful

See More Answers

Related Questions

Petco Pet Education Center
Health & Wellbeing
theres a red raised lump on my dogs leg
This kind of lump/growth needs to be ideally assessed by your veterinarian to have a definitive and specific answer. Usually there are two ways your vet can do that a part from examining it directly during physical examination. A biopsy can be taken under local or general anesthetic, otherwise a smaller sample through a fine needle can be aspirated (this technique is called FNA= fine needle aspiration). Differentials include skin cysts, infections, benign or more sinister type of tumors. Please do not hesitate to contact us again on the forum or by requesting a consultation (where you can post pictures ) if you have any more questions or to discuss it any further.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog has had an inflammation to his leg as seen below - it has drastically changed size within the past 2 weeks. Is this a cause for concern?
Yes, this mass needs to be checked by your vet. There is no way for me to tell you what it is just by looking at a photo but it looks pretty serious. It is definitely a tumor but what kind it is, I don't know. I also don't know if it is malignant or benign. The best option is to have it surgically removed and then sent off for a histopathology.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello, my dog has a lump in front leg. I thought it is histiocytoma, but is not anymore round shaped, but slightly spread in the broad direction. I have pictures also.
Hi, and thanks for your question. Although a picture of it would help to give you a more specific answer, this lump/bump/growth should be ideally examined by your local vet to have a diagnosis established. Your vet may want to perform an FNA (fine needle aspiration) or a biopsy to sample the bump and determine its underlying nature. Differentials would include skin cysts, infections, benign or more malignant type of tumors. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
I’m curious to what this lump on my pup could be , I jus notice it today . It does feel hard . But she does bite in the are a lot . should I take her to the vet? Looks like it’s on the top of her back leg bone .
This lump/bump/growth should be ideally examined by your local vet to have a diagnosis established. Your vet may want to perform an FNA (fine needle aspiration) or a biopsy to sample the bump and determine its underlying nature. Differentials would include skin cysts, infections, benign or more malignant type of tumors. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello, can someone give me an idea as to what is wrong with my dogs leg?
Hello. It is difficult to say definitively, but this does look like a small tumor. It is best to have a veterinarian look to make sure as if it needs to be removed, doing so while it is so small is often very curative. Hopefully, it is not anything serious & thanks fir using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
There is a giant red lump on my dogs back leg. It’s also losing hair on it and around it.
That is quite a large lump on Laila's leg, and it could be a benign tumor or a malignant tumor. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of its cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. Once the cause of the lump is diagnosed, the vet can discuss treatment options if needed. Give her vet a call now to make an appointment. Best of luck.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hi my dog has a massive lump on his side of his back leg.near his back.it reminds me of when I had a cyst under my arm Pitt. It as exactly the same.
Pets can get many types of lumps and bumps. Most of these tumors will be benign but some will be malignant and you can't tell by looks. Here is a helpful link discussing the various types of skin masses in general: https://www.petcoach.co/article/lumps-and-bumps-on-your-pet/ Since mass is large, I do recommend to have it checked out to be safe. From to photo, it looks like there's a pink area which could represent an impending rupture. The doctor may recommend to aspirate the mass to examine the cells under a microscope. That is one of the best ways to know what it is and if further action is needed. Hopefully it's nothing serious.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog has a red lump on her rear right leg just below the bend that has doubled in size since 1 week ago. It is about the size of a marble now and she seems defensive over it but otherwise doesnt seem bothered by it. Any idea what it is and any ways
That looks like it could be a growth of some sort, and it's concerning that it has doubled in size in a week. This is not something that can be treated at home. Any suspicious lumps should be examined by the vet. The vet can perform a test called a fine needle aspirate on it. To do this, the vet sticks a small needle into the lump to get a sample of its cells, and examines the cells on a slide under a microscope. It's usually painless to the animal, and relatively quick to perform. Once the cause of the lump is diagnosed, the vet can discuss treatment options if needed. I would give Athena's vet a call to make her an appointment. I hope this helps!
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My dog has a lump on her side grey round the edge pink in the middle one is now appearing on her back leg
The picture you posted was a little blurry, so it was difficult to evaluate, but in general we usually can't tell anything about a mass by just looking at it. Your vet can perform a simple test called a fine needle aspirate where they use a small needle to collect some cells from the mass, then look at them under the microscope. They may even need to send the cells to the lab for a pathologist to examine them, so we know what the mass is. If it is benign, you might not need to do anything about the mass at all, but if they see cells that worry them, they might recommend removing the mass. Good luck! I hope that was helpful. Thanks for using Boop by Petco.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
We've noticed a small lump/ bald spot on Luna's leg. It doesn't appear to be causing her pain or discomfort and when touched she doesn't notice it at all. We are planning on taking her to the vet on Tuesday to get it looked at, but if it is seething
It does not look like urgent at this stage. This kind of lump/growth needs to be ideally assessed by your veterinarian to have a definitive and specific answer. Usually there are two ways your vet can do that a part from examining it directly during physical examination. A biopsy can be taken under local or general anesthetic, otherwise a smaller sample through a fine needle can be aspirated (this technique is called FNA= fine needle aspiration). Differentials include skin cysts, infections, benign or more sinister type of tumors. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.
Updated on September 24th, 2025
image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Book Now

Sponsored