Mast cell tumors are a cancerous disease that is common in dogs. Usually found on the skin, this disease can also develop in other areas of the body. While most dogs that develop the disease have reached middle age, Mast cell tumors can develop in dogs of any age, breed or sex. In this article, we'll take a closer look at Mast cell tumors, their symptoms, and what treatments are available.
What are Mast cell tumors?
Mast cells are cells that work in conjunction with the immune system. They are distributed throughout the body to help fight infections and inflammation. Once dispatched to an affected area, they can release several different chemicals including histamine, heparin and serotonin. While these cells are vitally important in the body's natural defense against infection, they can severely damage the body when produced in excessive amounts.
When they are produced in large amounts, they are considered cancerous, and can cause damage such as gastric ulcers and internal bleeding. Most often, these cells will form tumors that usually are found on the surface of the skin, although they can also develop in the spleen, liver and bone marrow.
Which dogs are affected?
While Mast cell tumors can develop in dogs of any age, breed or sex, there are some breeds that do seem to be predisposed to inherit the disease. These breeds include Schnauzers, Bulldogs, Beagles, Boston Terriers and Boxers. While Boxers seem to have the highest risk in developing Mast cell tumors, the tumors are often not very aggressive. Although the cause of MCT is unknown, there are indications that the disease is inherited, may be associated with coats that are golden or red, or dogs that suffer from allergies.
Because these tumors can vary in size, appearance and location, the symptoms of Mast cell tumors can vary greatly. Very often, tumors will develop on the surface of the skin in the form of a lump. This lump can be pink or it could just be a lump under the surface of the skin. If it's pink, it could swell like hives when massaged. Other symptoms could include vomiting, diarrhea, loss of appetite, dark stools and general weakness.
Diagnosis and Treatment
Diagnosis usually begins when a dog handler has noticed a growth on his dog. A veterinarian will then take a sample of the tumor to perform a preliminary biopsy, draw blood in order to perform a blood test, and eventually the whole tumor will have to be removed to perform a full biopsy. Other tests could include a urinalysis, x-rays, ultrasound, and tests on the lymph nodes and bone marrow. Once a diagnosis has been made, the veterinarian will assign a grade to the tumor (Grade 1 tumors have the best prognosis; Grade 3 are very aggressive) and a stage to the disease. Stage 1 is very early and has a very good prognosis, while Stage 4 is very progressed and is usually terminal. Treatment will vary depending on the severity of the disease. In very early cases, removing the tumor will be all that is necessary, while further progressed cases will likely undergo chemotherapy. In the worst cases, the only thing to do is to try to make the dog comfortable until the quality of life begins to fade.