What is a Mast Cell Tumor?

Mast cell tumors are a type of cancer of the blood cells that are normally involved in the body’s first response to inflammation and/or allergens. This type of tumor in dogs is most common to appear on the skin but it can also affect other organs such as the spleen, the liver, the gastrointestinal tract, and the bone marrow.
Certain dog breeds are predisposed to these tumors. These breeds are Boxers, Boston Terriers, Bulldogs, Pugs, and Golden Retrievers. Rarely, any other dog breed can develop a mast cell tumor.

Because the most usual place for a mast tumor to appear is the skin it can appear as a small bump and very fast can become very big and disseminate through the body. The behavior of these tumors can vary and they can stay the same size for months but also can grow very big very fast. The most common organs for metastasis of a mast cell tumor are the spleen, the liver, and the nearby lymph nodes.

Diagnosis of a mast cell tumor

For a definite diagnosis of a mast cell tumor, the veterinarian will perform a biopsy or a fine needle aspiration. The results will determine if the tumor will be treated surgically, with radiation or chemotherapy.
If there are clean margins and no metastasis to other organs, surgical excision of the tumor is curative.
Sometimes, additional supportive therapy is given such as prednisone (a steroid known to kill cancerous mast cell and decrease inflammation), antihistamines and antacids.

If the mast cell tumor is located only on the skin and there is the possibility of full surgical removal the prognosis is good. If the mast cell tumor is located in the liver, spleen or the gastrointestinal tract the prognosis is very poor.

 

In the video below you can see an amputation of a forelimb due to a mast cell tumor. 

 

 

If you liked this video, read “Mast Cell Tumors in Dogs” on our blog.