Mast Cell Tumor Diagnosis: JD’s Biopsy Results Revealed Mast Cell Tumor—You Don’t Know What the Bump Is Unless You Look at the Cells

Nobody, not even a veterinary oncologist, can identify a bump just by looking at it.

There is no point in guessing and there is no point to watch potential cancer grow. Don’t wait. Aspirate.

Mast Cell Tumor Diagnosis: JD's Biopsy Results Revealed Mast Cell Tumor—You Don't Know What the Bump Is Unless You Look at the Cells

JD’s story

We found three bumps on JD which we had checked out last week. One of them, looking like a skin tag, is a skin tag. We had the other two aspirated because no matter how much you stare at or play with a bump, you cannot tell what it is by doing that.

One of JD’s bumps was preliminarily thought to be a lipoma and the other one probably a cyst. JD is another example why you want to biopsy every bump you find, no matter how little and how innocent it might look.

Biopsy results

The biopsy results came back this morning.

The bump on his thigh is indeed a lipoma as thought. There were no suspicious findings on that one. The other one, however, is not a cyst after all.

The bump on JD’s tarsus is a mast cell tumor.

Tiny, innocent-looking little thing. Not at all the typical lesion, you’d expect to see. Yet not so innocent after all. Mast cell tumors can indeed look like anything or look like nothing much at all.

What is a mast cell tumor?

A mast cell tumor (MTC) is cancer of specialized, histamine-releasing immune cells found in connective tissue – mast cells. MTCs account for up to 20% of skin tumors in dogs. If we’re lucky, surgery can be all the treatment needed. The biopsy result says that the cells show mild atypia.

JD is perfectly happy and doesn’t know he should be worried about something.

Mast Cell Tumor Diagnosis: JD's Biopsy Results Revealed Mast Cell Tumor—You Don't Know What the Bump Is Unless You Look at the Cells

Identified it early

The upside is that JD’s tumor is very tiny and now we know what is is. 

JD is scheduled for surgery on Friday. Then another biopsy and staging of the tumor. Surgery is the treatment of choice for MCT, and often the only treatment needed.

I’m a bit concerned about the location because where it is there isn’t much surrounding tissue to remove at all. Will we be able to get clean margins? Ideally, two centimeters of tissue should ideally be removed all around. But there isn’t much of all around there. We may or may not have to follow the surgery with radiation therapy. For now, we’re going to get it out and see what else needs to be done.

Aspirate every bump

JD’s bump isn’t the only example of why it is important to aspirate each and every bump.

I was following what I believed was the best thing to do but at times I wondered whether I was being overzealous. But clearly, I was not.

Don’t wait, aspirate.

Related articles:
Canine Mast Cell Tumors: JD’s Mast Cell Tumor Diagnostics, Strategy, and Treatment
Mast Cell Tumor Treatment: JD’s Mast Cell Tumor— Surgery and Pathology Report

Further reading:
Your Dog Has a Mast Cell Tumor, Now What

Categories: Biopsy • Cancer • Conditions • Diagnoses • Dog health advocacy • Fine needle aspirate • Lumps and bumps • Mast cell tumors (MTC) • Symptoms

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Jana Rade

I am a graphic designer, dog health advocate, writer, and author. Jasmine, the Rottweiler of my life, was the largest female from her litter. We thought we were getting a healthy dog. Getting a puppy from a backyard breeder was our first mistake. Countless veterinary visits without a diagnosis or useful treatment later, I realized that I had to take Jasmine's health care in my own hands. I learned the hard way that merely seeing a vet is not always enough. There is more to finding a good vet than finding the closest clinic down the street. And, sadly, there is more to advocating for your dog's health than visiting a veterinarian. It should be enough, but it often is not. With Jasmine, it took five years to get a diagnosis. Unfortunately, other problems had snowballed for that in the meantime. Jasmine's health challenges became a crash course in understanding dog health issues and how to go about getting a proper diagnosis and treatment. I had to learn, and I had to learn fast. Helping others through my challenges and experience has become my mission and Jasmine's legacy. I now try to help people how to recognize and understand signs of illness in their dogs, how to work with their veterinarian, and when to seek a second opinion. My goal is to save others the steep curve of having to learn things the hard way as I did. That is the mission behind my blog and behind my writing. That is why I wrote Symptoms to Watch for in Your Dog, which has turned out being an award-winning guide to dog owners. What I'm trying to share encompasses 20 years of experience.

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