It is normal for our dogs to get a little lumpy and bumpy as they age, and these skin growths are one of the major reasons pet owners seek veterinary care. By far, most of these lumps are benign, but the possibility of skin cancer is alarming; and that little bump can end up being fatal if the diagnosis comes back ìMCTî or mast cell tumor. MCT is the most common malignant skin cancer in dogs.†What is a mast cell?Mast cells are a type of white blood cell and part of the immune system. They are one of the bodyís first line of defense against invading organisms, and they assist in wound healing. The majority of mast cells are found in the skin and the lining of the intestinal tract. But mast cells have a downside. Histamine is one of the chemicals they contain, and that makes them play a major role in allergy and immune related diseases.†Mast cell tumors account for about 20% of all tumors found in the skin. They can take many different forms, from a slow-growing and isolated mass to ulcerated and fast growing. They can be itchy and diffuse and show up on any part of the body. (see photos) The earlier these tumors are found and treated, the better. Of course, the small ones are easier to treat than the large ones ó so get seen early!Some breeds are more prone to this cancer. The major ones are Boston terriers, boxers, pugs and bulldogs, as well as golden retrievers and Labrador retrievers. However, any breed of dog can develop this skin cancer.†Diagnosis, treatment and gradingWhen these bumps are biopsied, they should be graded so your veterinarian can make predictions on tumor behavior and to help with therapy. They are graded from least to most aggressive ó Grade 1, 2 or 3.Most mast cell tumors are diagnosed by fine needle aspirate (FNA), which is a simple procedure that can be done by any veterinarian. Surgical removal remains the primary treatment for mast cell tumors. It is important to make sure your veterinarian is comfortable removing these tumors ó incomplete removal can lead to recurrence.†For higher grade tumors, chemotherapy or radiation therapy is used.Some mast cell tumors can arise from deeper tissues just under the skin. These types of subcutaneous mast cell tumors often are mistaken for fatty masses (lipomas). These act differently and normal grading is not effective.Mast cell tumors can be successfully treated and cured in many cases. Small, isolated lower-grade tumors have an excellent prognosis if caught early. Unfortunately, the less common high-grade tumors have a poor prognosis, with most dogs dying of their disease in less than one year ó even with aggressive chemotherapy.The cancer you can seeOverall, we cannot see most cancers as they grow in dogs and cats. So often a fatal cancer grows in the lungs, abdomen or brain; and we donít know it. This leads to a sudden and ìend stageî diagnosis in many cases that takes us by surprise. But in the case of skin cancer, you can see it in the early stages and get it evaluated. You can monitor these and get help early – that is the key to prevent being surprised by a fatal prognosis.About 75% of the cases we see in our practice are end-stage cancer. It seems like an epidemic of these horrible diseases that take our great pets away from us. Please, if you see a lump or bump, have it seen by your veterinarian.
Dr. Jim Humphries is a veterinarian and provides hospice and end-of-life care for pets in the Colorado Springs area. He also serves as a visiting professor at the College of Veterinary Medicine at Texas A&M University. He lives in Falcon with his wife, horses and Great Danes. https:// www.HomeWithDignity.com
