Petco Text Logo
Petco Pet Logo

Dog's leg swelled after vet said cancer. Is it a tumor or fluid?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed | Male | neutered | 10 years and 9 months old | 70 lbs

went to vet with normal size leg very tiny bump, leg gone aggravated at vets and in the car on the way home, later that day leg and paw grew to 2 x the size, has grown more since. vet said they thought dog had cancer, my question is is this growth a fatty tumor or perhaps fluids?

This question includes photos that may contain sensitive content. Click to view.

View more to consider that the photos may include sensitive content.

2 Answers

Most Helpful Answer

Image profile

Answered By Andrea M. Brodie, DVM

Veterinarian

Published on October 22nd, 2018

If I read this correctly your dog's leg was swelling to this size within a few hours. If your vet took x-rays and found bone lesions then there is indeed a possibility of bone cancer. However only a biopsy of the bone or the tissue of the swelling will prove that there is cancer. Without the possibility of examining the leg myself I can only give you possibilitites of why there is a swelling: 1) Check for puncture wounds or an injury. this could be a peracute infection of the joint. 2) this may be an injury of the joint such as a fracture or tendon injury, You should take your dog back to a veterinarian for an exam, especially since this is painful.

Vote icon

1Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Image profile

    Answered By Emily, DVM

    Veterinarian

    Published on June 17th, 2017

    This likely indicates increasing inflammation around the cancer area. While it is normal it does not relieve any pressure. It won't break open necessarily but if it becomes very swollen the skin may start ooze. You may discuss with your veterinarian more modalities for pain control as your dog will likely get more painful as the site gets more inflamed.

    Vote icon

    1Pet Parents found this answer helpful

See More Answers

Related Questions

Petco Pet Education Center
Health & Wellbeing
3 days ago I noticed my dog had a swollen back foot/leg. I took her to the vet yesterday and we were given antibiotics and pain meds. I just wanted to know if any doctors have seen anything like this and what you think it could be my vet said to fini
I can see the swelling from the pictures you posted. It appears the swelling goes form the foot all the way to the knee. I see that you live in an area where snake bite is possible. I would check thoroughly for any punctures along the entire leg and see if Diamond is painful in any particular area. If not, other causes of swelling like this could include infection, allergic reaction, trauma, cancer, among others. Sometimes swelling in an entire limb can be caused by decreased lymphatic flow - this can be caused by damage to lymph nodes or a structure under the skin or inside the body that is impinging on the lymph flow. I have also seen swelling like this with a flare-up of a mast cell tumor elsewhere on the body. I agree with your vet; if the medications prescribed to not make a difference, additional diagnostics are warranted. They may include bloodwork, abdominal x-rays, tick testing, or sampling of any small masses found.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Not lamesudden swelling of hock. Feels like the tendon and joint are involved. Squishy and feels like grissel. Hot. Took her to vet for xray, waiting for more followup in a few days. Im so worried about cancer after losing a dog a year ago. Put her o
I cannot give you a definitive answer to your question just by looking at the is one x-ray. I can't get a good look at the x-ray as it won't enlarge enough for me to see what I need to see. Regardless, I think I see a lucent area on the calcaneous. That could be cancer but it could be osteomyelitis (bone infection) or even a fungal infection. It does not appear to involve the joint. The calcaneous is not at typical area to get bone cancer if that is any consolation. It is not impossible, just not common. This could be a hygroma (inflammation of the bursa) but without examining her myself it is too hard to say. I think your vet needs to aspirate the mass and look at the fluid under the microscope - usually you can see if there is bacteria in there (I would be worried about this so she really should be on some antibiotics) or cancer cells or just inflammation, etc. ( https://www.drsfostersmith.com/pic/article.cfm?articleid=2847 ) Hope this helps. Best wishes.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
My 5yr old Rottie cross boy had tto surgery on his hind leg 7 months ago and was doing fine. Yesterday I noticed a swelling halfway down his tibia. He is not lame but the lump is warm and a bit tender to the touch. He was running around playing with
This sounds more like an area of infection. Bone cancer usually doesn't have a warm swelling to start, and an infection does. With cancer the bone itself would be painful. Usually with bone cancer you see a lameness before any visual changes. Do bring him in for an exam when you can. He may need antibiotics if this is an infection. Thanks for using Boop by Petco to help you care for Ted.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
After an earlier post about Harvey, he has taken a turn for the worse. He has now developed small lumps all over his body (calcium deposits) and large lumps over the past couple of days around his neck. Last night he started to limp (leg fallen aslee
Oh no, I'm so sorry Harvey has taken a turn for the worse! Yes, it is possible that this is cancer, and if he has a swollen front leg and can bare little weight, I would be concerned that he is suffering from osteosarcoma (cancer of the bone). I would have him seen by a vet immediately to have his leg examined and x-rays. This will be very painful for him, and the x-rays can diagnose if he does have an osteosarcoma. Unfortunately, an osteosarcoma is a highly malignant, fast spreading type of cancer. Amputation of the leg is an option, and with amputation, the dog can have an addition three months of life depending on if the cancer has spread or not. I would take Harvey into a vet now. I'm sorry :-(
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hi my dog has had this lump on her front right leg for about a month now and out of no were it got very big it is not solid it feels like fluids are inside but also doesn’t seem to bother her but I no it does I need answers so bad
Oh that's quite large! This could be a cyst, 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 Mj's vet a call to make her an appointment. Best of luck.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
I have a labradore of 5 yrs female. She had a tumour which was removed by a vet 15 days earlier but i think she is having hard swelling again on 1st and last stiche. please suggest me is this an infectious cancer or what it is and how it will be trea
The ends of the incision look infected and very painful. She should be rechecked right away for medication for pain and swelling and further antibiotics. She may need some parts opened and drained and flushed to help minimize the infection. If the tumor was cancerous and it was not completely removed, then there is a change the cells are angry and irritated and growing again from inflammation. Try to apply a warm compress and keep the area clean until you can get her in.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello . I have a purebred blue nose pit bill who's 9 yes old we recently found out that he has cancer ( he was huge lumps all over him) but it wasn't until recently my husband noticed that our dogs back left leg is very swollen. In the pictures I'm s
Poor Blue! His leg is quite swollen, and unfortunately there are no OTC medications you can give him for pain and swelling. Many human pain medications are toxic to dogs, and can be fatal if given. He does have to see a vet as soon as possible for his swollen leg, as this will be painful for him. I would see if you can borrow money from family and friends, and I can give you some resources that may help as well. You can see if your vet accepts payment plans, if there is a low cost clinic in your area, or you can apply for Care Credit online. There is also an organization called Red Rover that give grants for treatment of sick animals, and you can see if you qualify for one of their grants. Best Friends also has a list of resources that offer financial assistance on their website. http://www.humanesociety.org/animals/resources/tips/trouble_affording_pet.html?credit=web_id91754962 https://www.redrover.org https://www.carecredit.com http://bestfriends.org/resources/financial-aid-pe
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Hello, my dog developed a hairless bump on his leg. It started growing so I went to my local pet store and they recommended an ointment to try first. The width in size didn’t change but the bump got flatter with the ointment.. now, I believe the bump
This does have a few characteristics of a cancerous tumor, so it's best to have him seen by a veterinarian as soon as possible. The center of the tumor does appear infected, which can happen with certain tumors as they grow. The veterinarian will help to narrow- down the specific type of tumor this is by doing some tests. Regardless of what it is, it will likely need surgical removal. It's best to remove this as soon as possible, because these can quickly become inoperable and require amputation. Below is a link to more information about lumps and bumps in dogs. https://www.petcoach.co/article/lumps-and-bumps-on-your-pet/ I hope that helps and Drako gets better soon.
Updated on September 24th, 2025
Petco Pet Education Center
Health & Wellbeing
Zoey has been diagnosed with bone cancer in her front right leg about 3 weeks ago. Have decided not to amputate Have her on Rimadyl The swollen area appears to have light blood spots today. Will this break open to relieve pressure? And is this nor
This likely indicates increasing inflammation around the cancer area. While it is normal it does not relieve any pressure. It won't break open necessarily but if it becomes very swollen the skin may start ooze. You may discuss with your veterinarian more modalities for pain control as your dog will likely get more painful as the site gets more inflamed.
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
image
Have A Vet Question?

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

Book Now

Sponsored