Mast Cell Tumors, part 2

July 10, 2009

Mostly good news. We got the cytology report today, and Jasmine’s mast cell tumor (MCT) has the following characteristics:

  • Grade II. We would have rather had Grade I, but this is still much better than Grade III.
  • Well-differentiated. This is a term that is more commonly associated with Grade I (in contrast to moderately- or poorly-differentiated). So maybe this means we’re on the low side of Grade II. I’m going to go with that.
  • Clean margins in all directions, including underneath. Thanks to our surgeon for being so thorough, and to Sarah for helping us find it so early.
  • Low Mitotic Index (MI). This may be the most important thing. According to a UC Davis study, “MI is a strong predictor of overall survival for dogs with cutaneous MCTs and should be included as a prognostic indicator when determining therapeutic options.”

Bottom line: no further treatment is indicated or recommended. The doctor also reassured us that skin MCTs don’t usually progress to the internal organs – those more commonly just start there. And since she had an abdominal ultrasound just a few weeks ago (completely unrelated) that cleared both her liver and spleen, I think we’re in pretty good shape on that.

So, a big sigh of relief, at least for now. And now we implement a more aggressive schedule of body checks on all of the dogs – to include the limbs. Until now, we have focused more on the torso because that’s where the lipomas tend to crop up. The key to these MCTs is to catch them early and get them the heck outta there.

Again, thanks to all of my friends for the well-wishes. And thanks also to our vets at North Park Veterinary Clinic in Rohnert Park, especially Dr. Miconi who diagnosed the MCT and is doing the follow-up, and Dr. Schweid who performed the surgery.

Jasmine the pirate queen in her "half-pants".

Jasmine the pirate queen in her "half-pants".

Another view of the pirate pants.

Another view of the pirate pants.

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Mast Cell Tumors, Part 1

July 8, 2009

Well, based on the encouragement of two friends named Ellen, I decided to start a blog. I didn’t expect my first post to be such a serious topic. But here we are.

Last Sunday, after a perfect Standard run, Jasmine was getting a cool-down massage from my friend, Sarah Johnson. She (Jasmine) is prone to harmless lipomas, and Sarah and I had talked about two new ones that had recently popped up on her abdomen. As Sarah was massaging her, she discovered a lump on her hind leg. Confused by the location, she asked me if this was one of the new lipomas. YIKES, NO!!! Lipomas are loose smooth lumps under the skin that are barely noticeable unless you happen to feel them. This thing was a horrible, discolored fleshy mass about the size of a cherry that protruded through the fur. But it was buried in her hock feathers, so was not immediately apparent until it was discovered by palpation.

After consulting with friend and RVT, Katrina Parkinson, I learned that I should leave the mass alone until it could be examined by a vet. If it did turn out to be a mast cell tumor, apparently they can get angry with the least provocation and produce a huge release of histamines that can lead to anaphylactic shock. Don’t mess with it – got it!

With this new distraction, I botched my timing on her Gamblers close, but she pulled off decent runs in Pairs and Jumpers. We packed up and headed home, hoping that a trip to the emergency room would yield an easily-treatable foxtail abcess. When we arrived at home, we called our local emergency clinic, and not recognizing the name of the doctor on duty, we waited until 7pm until our “regular” doctor showed up. Why do we have a “regular” doctor at the emergency room? Because it seems that over the last couple of years, all of our dogs tend to get in trouble on Sun-Tues between 7pm and 7am. But I digress.

We arrived just after 7pm, shortly before all hell broke loose and our preferred doc got tied up with traumas and allergic reactions. We were greeted by the day doc, who is not on the regular staff (holiday weekend coverage, I guess). He had the bedside manner of a Mack truck, and apparently, the diagnostic skills to match. We were left with words to the following effect: It’s not a foxtail, we’ll send the smear out for cytology review, you need to follow up right away with your regular vet, and there’s nothing palliative for us to do tonight. Yes, he actually used the word “palliative”. How do you think that made us feel? Cha-ching, no answers and nothing but worry for us.

Monday morning, we decided to start over with our regular vets at North Park Veterinary Clinic. Apparently, Dr. Miconi’s skills with a smear and microscope are better honed, as she immediately recognized the aspirated cells as consistent with mast cell tumor. I suppose it helps that her own dog has a long history of these things. She advised immediate surgical removal, and since they were able to fit her in the schedule that day, that was that. Fortunately, we had anticipated this outcome and hadn’t fed the dog that morning so she was good to go.

We picked her up at 4pm with a bit of a hangover and a 7″ incision from ankle to thigh. The goal with mast cell tumors is to clear a 2-3cm margin on all sides because the tumors are generally poorly differentiated. That is a little tricky on the leg (at least horizontally) because they have to do a balancing act between excising enough tissue to be safe, and leaving enough skin to close the wound. As a result, the skin is very tight and we have to limit her activity so it doesn’t tear.

In the meantime, I have learned a little more about mast cell tumors. Once the tumor tissue is removed, it is sent to a pathologist for grading and staging. Grading is the key, as the grade (I-III) determines the aggressiveness of the tumor and how likely it is to be malignant. Grade I means that no further intervention is required and we just need to watch out for new tumors. In addition, the staging (0-IV), as we probably all know from human cancers, is an indication of how far the tumor cells have spread through the body. So now we wait, and hope for Grade I. The pathology results take 4-6 days, which means we should know more by Friday.

In the meantime, here’s a nice photo of her incision. I wish I had a picture of the original tumor, but it didn’t occur to me until too late.

Incision from removal of cherry-sized mast cell tumor

Incision from removal of cherry-sized mast cell tumor

Thanks to our friends at Drs. Foster and Smith (one of my favorite online vendors) for providing PetEducation.com, the source of referenced articles in this post for both lipomas and mast cell tumors. And thanks also to all of the kind words and well wishes that my friends have sent me through Facebook and e-mail.