My beloved dog Bogie had these weird, pink, fleshy growths which first appeared about 10 years ago. At the time, he also seemed a little off and was vomiting. I was beginning my career as a registered veterinary technician, and I had learned to have any strange or new lumps checked out. The veterinarian examined the lumps and advised to give an injection of Benadryl to Bogie. This was so she could perform a fine needle aspirate, which involves taking a small needle and inserting it into the lump to gather some cells. Thankfully, this is a minimally invasive procedure, which can usually be done with your animal awake. The veterinarian then examined the cells under a microscope. After waiting, which seemed like forever, she came back out and told me that he indeed had cancer. Mast cell cancer to be exact. I was devastated, but Bogie’s doctor tried to console me with information about the disease. This is what I hope to pass on to you.
Mast cell tumors are a cancerous process of mast cells and account for between 15%-20% of skin cancers. Mast cells are present in the skin, and usually, fight inflammation and allergic reactions by producing histamines. These mast cells, however, can congregate and form a tumor. This disease comes in different severities, with stage III being the most malignant, or aggressive. The reason my veterinarian administered a Benadryl injection was any time this tumor is disturbed, like for a needle aspirate, it can release toxic granules which spreads this cancerous process throughout the body. Benadryl is an antihistamine that will suppress this explosive process.
Once Bogie was diagnosed with mast cell tumors, the staging process began. This involved chest radiographs, bloodwork, and an abdominal ultrasound to see if the tumor had metastasized to anywhere else in the body, like his lungs or abdomen. In our case, Bogie’s mast cell disease seemed to be localized to his masses. My veterinarian arranged to have a veterinary surgeon come in to remove the masses. The tumors were in a very awkward spot (in his armpit and chest area), but the surgeon was able to remove them with clear margins. This meant there was no cancer detectable in the outer areas of the tissues submitted to the lab. The tumors were “low grade” which means a low level of malignancy. Bogie was cancer-free! I was happy to have the mast cell tumors removed, but I knew eventually they’d come back – because that’s what they do.
Fortunately, we have many treatment options for mast cell tumors in dogs. Surgery is often recommended to remove the mast cell tumor. Radiation and chemotherapy are also available if indicated for your pet’s specific tumor. There is a new method of “removing” these tumors. It’s called Stelfonta. In very simplified terms, it’s a drug injected into the tumor and will cause it to die off or necrose. This method is not without risk, so a thorough discussion should be had with your veterinarian.
Mast cell disease is a disease of the skin and of the intestinal tract. Even if our staging diagnostic testing comes back clear, one must realize that it’s impossible to truly see it all. This is where diligence comes into play. Any new, weird, growing lumps, or lumps that change in size, should be checked by a veterinarian. My Bogie has had mast cell tumors removed four times now, over the past 14 years. Thankfully, they’ve all been low grade. I attribute this to my fastidiousness of always having new lumps checked out and removed if warranted. Make sure you check those lumps!
Our feline friends can also get mast cell tumors, but that is for another discussion. Please discuss any concerns you have about your pet with your veterinary team.