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Mast Cell Tumor in Dogs

Mast cell tumor is a common cancer in dogs.

Mast cell tumor (MCT) in dogs is a type of cancer that involves blood cells that normally functions as part of the dog's immune system, mast cells.

MCT is most commonly seen as skin cancer, but it can also be internal, affecting organs like the spleen, liver, or gastrointestinal tract.

Which Dogs Are Affected by MCT?

MCT is more common in certain dog breeds, such as flat-faced breeds like the Boston terrier and boxer. Retriever breeds are also more prone to MCT. However, MCT can occur in any dog.

Signs of Mast Cell Tumor in Dogs

Mast cell tumor can produce the following signs when it involves the skin:

  • A bump, lump, or area of hair loss on the skin that doesn't go away.
  • A bump on the skin that waxes and wanes in size. This is due to the nature of mast cells, which react to stimuli, so MCT lesions can get bigger and smaller as they react to irritations.
  • MCT appearance on the skin can look incredibly different each time. It may be red, ulcerated, swollen, large, small, or simply look like a raised area of skin.

When MCT occurs internally, the signs can vary widely depending on the system affected.

Diagnosis of Canine Mast Cell Tumor

MCT is diagnosed with a needle aspirate or biopsy of the affected area. Cells are taken from the mass or the entire lesion is biopsied or removed, and cells are examined under the microscope.

If MCT is diagnosed, additional tests to evaluate organ function and look for evidence of metastasis may be required. The pathologist will diagnose the stage of the MCT, and that will help define the prognosis.

Treatment of Mast Cell Tumor in Dogs

Some skin MCT can be cured with surgery if the surgeon is able to get the entire thing out. Those dogs must be monitored closely because dogs that develop MCT are prone to getting more lesions over time.

More surgery may be required if the pathologist determines that the surgeon didn't get everything out the first time. Radiation may also be necessary.

Dogs with metastasis or internal MCT may need chemotherapy.

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