Mast Cell Tumours

Mast cell tumour

Mast Cell Tumours

What is a Mast Cell Tumour?

Mast cell tumours (MCT) are the most common skin tumour found in dogs. They can also affect other areas of the body including the spleen, liver, gastrointestinal tract, and bone marrow. Some breeds are predisposed to MCT – Boxers, Staffordshire bull terriers, Beagles, Weimaraners, Rhodesian ridgebacks, Shar-peis, Golden retrievers, Labrador retrievers and brachycephalic breeds. Typically, middle-aged to older dogs, though any dog can be affected.

MCT comes in all shapes and sizes. They can occur anywhere on the skin though more commonly will be found on the limbs or trunk in dogs. Lumps can seem to wax and wane or ‘flare up’, becoming larger and inflamed sometimes. This is due to histamine release from the tumour.

If you notice any lumps or bumps on your dog, bring them into the clinic so we can take a look for you and take a quick sample in consult.


Diagnosis of MCT is simple. We will take a fine needle biopsy of the suspicious mass. We can then look under the microscope in search of abnormal mast cells.

MCT can be either low, intermediate or high grade. This can be determined through histopathology of the mass after removal or biopsy.


Treatment of choice for MCT is surgery. We surgically remove the mass under anaesthetic. With MCT we take wide margins to make sure we get the whole thing. We then send the mass for histopathology to grade the tumour. Complete surgical removal is often curative in dogs with low or intermediate grade MCT. For high grade tumours radiation therapy +/- chemotherapy treatments or further surgery may be required.

If you are concerned that your dog might have a mast cell tumour, Book an appointment online or call us today.

Click to read about mammary tumours.