Canine Mast Cell Tumors: Unraveling the Enigma and Navigating Treatment

Canine Mast Cell Tumors: Unraveling the Enigma and Navigating Treatment

The connection between dogs and their human companions is unmistakable, characterized by a deep and unwavering affection. As responsible caretakers of our canine pals, it’s only essential to grasp the significance of health concerns, like mast cell tumors (MCTs) in dogs. Let’s explore MCTs and the cutting-edge treatment choices that are accessible.


What are Canine Mast Cell Tumors?

Mast cell tumors, though a pet parent’s worst nightmare, are something every dog owner should be aware of. These tiny troublemakers are the most common form of skin cancer found in our beloved canine companions. Think of them as sneaky, shape-shifting cells hiding in your dog’s skin. Mast cells, the good guys in our pup’s immune system, can turn rogue and become cancerous when they start multiplying uncontrollably. These tumors often masquerade as harmless warts or benign lumps, making them incredibly tricky to spot. They can pop up anywhere on your fur baby’s body, and that's what makes them even scarier.

What’s more, mast cell tumors aren’t just about appearance; they can also trigger severe allergic reactions in our dogs, putting their lives in danger. Even for veterinarians, identifying these crafty culprits just by looking at them is like finding a needle in a haystack. So, if you notice any unusual skin masses on your furry friend, especially if they’re middle-aged or belong to breeds like Boxers or Boston Terriers, don't hesitate to consult your vet. It’s always better to be safe and get those mysterious lumps and bumps checked out, for your pup’s well-being and your peace of mind.


Recognizing Canine Mast Cell Tumors

Mast cell tumors can be like silent troublemakers, lurking in your furry friend’s skin without making a peep. That’s why we pet parents must play the role of vigilant detectives. Veterinarians suggest giving your beloved pup a once-over every few months. Look for any mysterious lumps or bumps on their skin – it’s like a health treasure hunt. But be on the lookout for the following signs, and when you spot them, it’s time to sound the alarm and call your vet:

First, keep an eye out for new, unexpected skin lumps. Second, if there’s a lump you’ve known about that starts changing in size or color, don’t ignore it. And third, a sudden and unexplainable allergic reaction or hives in your fur baby might be a red flag.

Mast cell tumors come in all shapes and sizes. Some of them might be tiny, moveable masses just beneath the skin, with barely any swelling. Others can be more aggressive, showing up as larger, hairless sores that are impossible to miss. But here's where it gets emotional – sometimes, these sneaky tumors can create havoc. They can trigger strong allergic reactions when they awaken the immune system. And if, by accident, you bump or disturb the tumor, it might go into a dramatic “degranulation” mode, releasing all its inflammatory contents at once. This can lead to distressing symptoms like swelling, redness, or, in rare cases, a severe anaphylactic reaction. Picture your furry companion feeling weak, nauseous, vomiting, and having diarrhea, or worse, their face and limbs swelling up. In the rarest of cases, it could even lead to a heartbreaking collapse or, in the most extreme situations, loss. So, let’s be diligent and safeguard our pets’ health and happiness.

MCTs present as small lumps or bumps on or beneath the skin. They can vary in appearance, making them tricky to identify. Some may remain the same size for long periods, while others can rapidly change in size. Signs of MCTs include swelling, redness, ulceration, or sudden lameness if located in a limb. Prompt veterinary consultation is crucial if you notice any abnormal growth on your dog’s body. A veterinarian will typically perform a fine needle aspirate or biopsy to diagnose MCTs definitively.

Treatment Options

Various treatments are available for mast cell tumors, and they can be employed individually or in combination to ensure the well-being of your furry family member. Let's delve into the detailed options:

Surgical Intervention. This is ideal for dogs with low-grade mast cell tumors that haven’t spread, surgical removal stands out as a primary treatment. However, it’s crucial to note that surgery alone may be insufficient if the tumor has metastasized. Consideration should be given to older dogs with underlying conditions and heightened anesthesia risks.

Radiation Therapy. When wide surgical excision is not feasible, combining radiation with surgery becomes the optimal approach for managing mast cell tumors. It’s essential to be aware of the drawbacks, such as the cost and the need for repeated sedation during treatments.

Chemotherapy. This treatment is tailored for dogs with multiple or high-grade mast cell tumors, as well as those with tumors in regional lymph nodes, chemotherapy utilizes medications like Vinblastine, Lomustine, Leukeran, and the home-administered Palladia (toceranib). The latter comes in an oral form, providing a convenient option for at-home use.

Intratumoral Injections. This option is a groundbreaking discovery for non-metastatic mast cell tumors such as Stelfonta (tigilanol tiglate). Administered directly into the tumor, it boasts the potential to eliminate up to 75% of the tumor with a single treatment.

Oral Medications. Prednisone, a cost-effective and generally safe medication, is commonly used. It shields the body from histamine, heparin, and enzymatic granules released during mast cell degranulation. Prednisone can aid in shrinking the mast cell tumor, facilitating easier surgical removal.

Antihistamines. Some dogs with mast cell tumors find relief with antihistamines. Elevated histamine levels in these cases can impact blood pressure and heart rate, and cause ulcers. Examples include H1 blockers like diphenhydramine (Benadryl) and H2 blockers like famotidine (Pepcid).


Is Surgical Removal Recommended for Dogs with Mast Cell Tumors?

Yes, opting for the removal of mast cell tumors is the preferred treatment. Mast cell tumors, despite their appearance, have invasive characteristics, requiring a proactive and thorough surgical approach.

When we mention “aggressive removal,” we mean surgically extracting the tumor with wide safety margins. In cases where there are changes in nearby lymph nodes, it’s essential to surgically remove them to enhance the success of the treatment.

After the mast cell tumor is removed, it undergoes further examination (cytology and histopathology) to evaluate whether it was completely removed.

If the surgical margins of the removed mast cell tumor are not wide enough, the veterinary oncologist may recommend a second surgery or additional treatments, such as radiation.


Future Avenues in MCT Treatment

As our knowledge of canine mast cell tumors (MCTs) grows, we’re expanding our arsenal of treatment approaches. Exploring gene mutations associated with MCTs has paved the way for personalized medicine and innovative targeted therapies.

One prime example is the identification of the c-Kit mutation in certain MCTs, leading to the development of targeted medications like Palladia. Looking ahead, treatment horizons may encompass immunotherapy, harnessing the power of a dog's immune system to combat cancer cells.

Another exciting frontier in cancer care is Nanotechnology. Crafting nanoparticles tailored to deliver anti-cancer drugs directly to tumor cells holds the promise of enhancing treatment effectiveness while minimizing potential side effects.


What’s the Outlook for Your Pup Facing a Mast Cell Tumor?

When it comes to mast cell tumors in our furry friends, the prognosis is a bit like predicting their playtime in the sun. After surgery, dogs can typically enjoy around six months of wagging tails. Add some chemo love to the mix, and that joyful play extends to a median survival time of a year.

The survival expectancy depends on the mast cell tumor’s grade (grade I, grade II, or grade III). Most of the time, mast cell tumors grade II and grade III are considered high-grade tumors and do not have a favorable prognosis. 

Now, is a mast cell tumor a canine calamity? Well, it can be, but it’s not always the case. According to research, high-grade tumors throw a 61% fatality rate into the mix. On the flip side, the low-grade ones, the vast majority of cases, boast a lower fatality rate of about 16%. So yes, it’s serious business, but with the advances in veterinary medicine, especially in the oncology realm, a mast cell tumor doesn’t have to be fatal. However, it certainly needs to be caught early for the treatment plan to be successful. 



Dealing with canine mast cell tumors may seem daunting, given their frequency and potential severity, but it's a hurdle we can overcome. Thanks to advancing diagnostic tools, an expanding range of treatment choices, and groundbreaking research, we now have more effective weapons against this disease.

As devoted dog owners, our responsibility is to stay vigilant and take proactive measures for our furry friends’ well-being. Regular check-ups with the vet, prompt attention to any unusual growth, and a grasp of the available treatment avenues are crucial actions. By combining love, knowledge, and the progress of science, we can navigate the journey through canine mast cell tumors, ensuring the health and happiness of our beloved companions.