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

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.

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.

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 Petco Pet Education Center, formerly Petcoach to help you care for Ted.

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 :-(

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.

With this amount of pain and swelling he must be seen and assessed by a vet. A tumour or abscess may give such pain and deformity, but it is impossible to diagnose from a picture. There is no appropriate home remedies that can be recommended until the underlying cause is known and it is not fair to delay treatment in such a case

I have had many cases where the dogs/cats limp but don't seem overly painful. I think if you do not want a bone biopsy amputation is the best way to go because even with an invasive fungal disease most of the time you cannot treat the bone properly and you amputated to remove the fungal infection.