Grade Three Mast Cell Tumors in Dogs

If you notice your dog has a lump under its skin, it is important to seek prompt veterinary attention. While the mass could be harmless, you will want to rule out the possibility of a more serious condition, such as a mast cell tumor.

  1. Mast Cell Tumors

    • A mast cell tumor is a common skin tumor in dogs. According to the Washington State University College of Veterinary Medicine, mast cell tumors make up about 20% of the skin tumor cases in dogs. The tumor will appear as a lump or mass under the skin.

    Grade Three

    • Mast cell tumors are graded by severity from one to three. A grade three tumor is the most serious. It is aggressive, likely to spread to other organs and may be deep below the skin.

    Surgical Treatment

    • Mast cell tumors are removed surgically. Unfortunately, for grade three tumors, surgery alone may not get rid of the tumor completely, especially if it has spread. Grade three tumors may require more than one surgery for best results.

    Therapy Treatments

    • Chemotherapy is also used in cases of grade three mast tumors. Radiation therapy may also be used, especially if the tumor was not removed completely in surgery. However, this is usually done with lesser grade tumors that have not spread.

    Prognosis

    • The outcome will depend on a lot of factors, such as the location of the tumor, the success of the surgery, how the dog reacts to therapy and how far the tumor has spread. According to Dr. Gail D. Mason, DVM, MA, DACVIM, there is a 76% recurrence rate of grade three mast cell tumors following surgery.