Osteosarcoma in dogs – signs and what to do

Updated 2026-09-30 · 2 sources

Based on: PDSA, Science for Animal Welfare (UFAW), Genetic Welfare Problems of Companion Animals

Book a vet visit

Book a vet appointment if you think your dog has this – a vet needs to confirm it and plan the treatment. Osteosarcoma is bone cancer in dogs.

What to do now

What you can do now

Contact your vet for an appointment if you notice a hot, firm, painful swelling, limping or signs of pain.
Note when it started, how often it happens and what else you see.
Take a photo or short video to show the vet.
Let your dog rest somewhere calm.

Don't

Do not give any human medicine.
Do not wait if it gets worse.

What it is

Osteosarcoma is bone cancer that affects dogs.^[1] It can cause painful, hot, hard swellings, often on a leg, and limping.^[1]

Signs

Limping, from mild to severe
A painful, hot, hard swelling, usually on a leg
An unexpected leg fracture
Low energy
Reduced appetite
A swelling in the jaw bone
A painful mouth
A lump in the mouth
Difficulty eating
Discharge from the nose

Causes and risk factors

Irish Wolfhound
Rottweiler
Greyhound

How a vet finds out

X-rays
CT scan

How vets treat it

Surgery
Pain relief
Chemotherapy

Breeds prone to this

Veterinary charities list these breeds as more likely than others to get this condition. Each breed page lists the inherited conditions documented in the breed.

What the experts say

“Contact your vet for an appointment ASAP if you notice a hot, firm, painful swelling on your dog or if they are limping or seem to be in pain.”
— PDSA [1]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

OkPaw is on Android now – an iPhone version is on its way.

Common questions

What signs can osteosarcoma cause in dogs?

Signs can include limping, a painful hot hard swelling, an unexpected leg fracture, low energy, reduced appetite, jaw or mouth changes, difficulty eating and discharge from the nose.^[1]

How does a vet find out if a dog has osteosarcoma?

A vet may use X-rays and a CT scan.^[1]

When should I contact a vet?

Contact your vet for an appointment as soon as possible if your dog has a hot, firm, painful swelling, is limping or seems to be in pain.^[1]

Sources

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages