Overview
Mast cell tumours are one of the most common types of skin cancer in dogs, but can also affect internal organs like the spleen or liver. They form from mast cells — a type of white blood cell which plays a role in helping your dog deal with allergies or injuries. They can have lots of different appearances (including appearing like insect bites or harmless lumps). In any case, they can be serious.
Even though mast cells usually help protect your dog, cancerous ones can release chemicals like histamine in unpredictable ways. This can lead to swelling, irritation, or other symptoms (even in areas away from the tumour). Sometimes, dogs can get more than one mast cell tumour at the same time.
What are the symptoms of mast cell tumours in dogs?
Which dogs are at higher risk of mast cell tumours?
How are dog mast cell tumours diagnosed?
What treatments are there for dog mast cell tumours?
How do I help my dog recover from a mast cell tumour?
Can mast cell tumours in dogs be prevented?
FAQs about mast cell tumours in dogs
Are there any studies into dog mast cell tumours?
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Medically reviewed by Lizzie Youens, BSc(Hons) BVSc MRCVS
Published on 16/01/2026 • Reviewed on 16/01/2026