Reactive Dog, Vet Stuff

Mast Cell Tumors and my Dog

Mo gets lots of love from me, so that means he gets lots of pets.  There was a time when he wasn’t a big fan of affection, but he’s really come around.  In an article from vetSTREET, they explain that petting a dog has some benefits for you, like reducing anxiety and stress, lowering blood pressure, and decreasing heart rate.  There are also benefits for your dog:

  • Can help reduce anxiety and stress in dogs (must be done in the right spots)
  • Releases oxytocin
  • Can be used as a reward
  • The owner can regularly check the dog’s body

This last point is so important. Our dogs can’t tell us, “hey, I found something on my leg, can we get it checked out?” or “mom, my insides feel kind of funny, what’s going on?”  To help keep our animals healthy, it is up to us to watch for signs that they are not feeling normal or their bodies have changed.

Story Time

I found a bump on Mo’s side while I was petting him.  I didn’t think much of it at the time: it was small, he was only two, and he’s a mutt.  As time went on it stayed the same and I figured it was just a wart or a skin tag.  It didn’t seem like anything to worry about because he was acting happy and healthy and the bump didn’t seem to be causing any of pain.

Then the bump started to change.  It grew a little bigger and then it went from soft to hard.  That didn’t seem normal and everything you read about keeping human skin healthy says if a mole/bump/spot changes, go get it checked out!!

So that’s what we did.  At our vet appointment, I brought up the bump and the doc seemed concerned that it had changed shape and consistency. Her recommendation was that we get it removed right away.  A couple days later we were at the vet getting it removed.


The weeks after his surgery were long and hard.  The bump had been on his side, right by his back leg so we had to keep him still and that’s next to impossible with Mo and his energy levels. Not to mention the cone on his head made him extra miserable and every time he tried to get at the wound, the cone disturbed it.  This was a recipe for reopening a wound and back to the vet to get restitched.  It was a struggle.


During the healing process we got the results of the bump.  It was a Mast Cell Tumor.  The good news is that the entire tumor was removed and it was a low grade tumor.  Yay!  The only thing we had to do with that information was be thankful and to continually check for bumps as there is potential for recurrence of tumors.

So what is a Mast Cell Tumor?  According to VCA (Veterinary Centers of America), all dogs have mast cells and they serve important functions in the immune system and regulating blood circulation, skin, hair follicles, and fibrous tissue.  They are also factors in allergic reactions, wound healing, skin diseases, and tissue remodeling.

There are times when these cells mutate and cause tumors.  There are three grades:

  • Low: the cells are differentiated and have not spread to other areas of the body.  They are benign.  Prognosis: Very good!
  • Medium: these tumors show signs of being malignant and have grown below the skin.  Prognosis: Pretty good. Need to be aggressive with treatment, but high potential for recurrence.
  • High: these tumors are very aggressive, have started to spread to different areas of the body, and have developed under the skin.  Prognosis: Sadly, not very good in this case due to the spread and location of the cancer.

Fast Forward a Year

Right around January, I found a small bump on Mo’s head.  I waited a couple weeks to see if it was a cut from Lawrence and Mo roughhousing.  It didn’t go away and my heart sunk a bit.  Of course, when you catch these tumors early, things go well and we didn’t even know what this bump was yet.  As a dog mom or any kind of mom, you worry about you babies and I hated the idea of having Mo cut open again.  The pessimist in me also wondered about the future and how many times we might have to do this and what happens if one starts growing on the inside.

So we headed to the vet and because of this history and the size of the bump, they decided to sedate him and surgically remove the bump.  No cone and a less terrible location of the wound has lead to an easier healing process. Now to wait for the results!

The News

Luckily, our vet called right away with the news that it was not a Mast Cell Tumor, but a benign Pilomatricoma.  PetMD defines that big word as a tumor that “arise[s] from the cells that produce the hair follicles.”  These tumors are almost always benign.  What a relief!

Sedation sucks!

The takeaway here is to check your pets for bumps and lumps and take them serious!  You and your vet can decide together the best course of action.  Have you had any scares or noticed something not quite right with your pup?

4 thoughts on “Mast Cell Tumors and my Dog”

  1. As dogs grow older, frequently checking for lumps, bumps, etc. is even more important. We have had two masses removed from our dog in the last 18 months. We are very fortunate that they were both simply cysts, but the worry was there, as Soldier will be 20 years old next month. We’ve made it our mission to do a thorough check of his body every week. He thinks he is getting a massage, so it goes smoothly!

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