About Mast Cell Tumors

If, as a pet owner, you are reading this then there is a fair chance that your pet has been diagnosed as having a mast cell tumor (also called MCT or mastocytoma). If left untreated, mast cell tumors have the potential to lessen your dog's quality of life and may even be lethal. Your veterinarian is qualified to diagnose and treat such pathology.

Mast cell tumors are among the most common forms of cancer in dogs. The origin of mast cell tumors is a deregulated proliferation of normal cells in the skin (mast cells) that leads to a dangerously abnormal growth of these cells and formation of a tumor. It is not contagious to humans or other animals. Mast cell tumors have various forms and vary widely in size, shape, appearance, texture, and location. These tumors often behave in an aggressive manner, spreading to secondary body locations (metastasizing) and releasing chemicals that cause systemic problems such as loss of appetite, vomiting, diarrhea, abdominal pain, itchiness, lethargy, and anemia. Diagnosis of a mast cell tumor is usually made using a needle aspiration biopsy of the tumor, which for a positive diagnosis will typically show a large number of mast cells, although poorly differentiated mast cells may have few granules and be more difficult to identify. A surgical biopsy is required to find the tumor's characteristic grade.
 

• Grade I - well differentiated, and mature cells with a low potential for metastatsis

• Grade II - intermediately differentiated cells with potential for local invasion and moderate metastatic beahvior

• Grade III - undifferentiated, immature cells with a high potential for metastasis