Splenic Tumors in Dogs – a Lay Person’s View

February 24, 2011

Bad things happen in the spleens of dogs. I don’t know why, I just know they do.

Medically speaking, canine splenic masses typically start as unremarkable “nodules”. From there, they often transform into one of two types of masses: hemangioma (a benign tumor) and hemangiosarcoma (a malignant cancer). Other types of masses also occur but these two are the most common. Unfortunately, because the spleen is a vascular organ, even the benign ones often have tragic results.

In my experience (and that of many dear friends), splenic masses result in one of the following three outcomes, often without diagnosis or warning:

  1. They rupture and the dogs bleed to death
  2. They metastasize and the dogs die of cancer in other organs (lungs, brain)
  3. They get discovered by pure dumb luck and are dealt with surgically before #1 or #2 can occur

Scenarios #1 and #2 are tragic and I have far too many friends who have experienced one or the other. To protect the feelings of those who have suffered these tragedies, I will not name them. But I will give the following first-hand examples of #3 (with permission) – all three of these dogs were diagnosed accidentally as a result of unrelated events:

  1. Jasmine, my own 13-yr-old, had a frightening vestibular event (i.e. doggy vertigo) a few weeks ago. I have since learned that this is a rather common idiopathic condition in older dogs, but the neurologist that examined her determined that she wasn’t “classically vestibular”. In pursuing a differential diagnosis, an abdominal ultrasound was performed revealing a large abdominal mass. Urgent exploratory surgery resulted in the excision of a “fully-encapsulated splenic mass with no evidence of other organ involvement.” Final pathology results are still pending, but the preliminary assumption is that the surgery was curative. There is additional background to this story as you’ll see below.
  2. My friend Sarah, who specializes in canine rehab and massage, was routinely massaging her 14-yr-old Cruiser one night and felt a bulge under her rib cage. This lump was only apparent to sensitive hands and only when the dog was on her back. On examination, her doctor couldn’t even feel it but abdominal ultrasound revealed a splenic tumor which was then surgically excised. The dog lived another great year and eventually succumbed to complications of unrelated kidney failure.
  3. Just last week, my friend Liza’s 7-yr-old Taiko had an intestinal obstruction that required emergency surgery. While his belly was open, the surgeon observed a nodule on the spleen and elected to perform a splenectomy. Pathology report on the lesion suggested that it would have likely transformed into a splenic tumor (probably hemangioma) had it gone undetected.

Here’s a little more background on Jasmine’s story: in April of 2008, she spent a couple of days at Davis for a bout of hemorrhagic gastroenteritis (HGE). During her stay she had an abdominal ultrasound. They found nothing to explain the HGE, but did note some other abnormalities: a cyst on the liver and two nodules on the spleen. We were advised to follow up with another ultrasound in about a year. So we did. A scheduled ultrasound in June 2009 reported that the liver cyst was unchanged and the two splenic nodules were nowhere to be found. Excellent news, or so we thought. Not long after that I began having theoretical discussions with friends about the merit of routine ultrasounds, but we didn’t bother to do another one in the summer of 2010. Fast-forward to February 2011 and the crisis described above.

I found a terrific article that explains in much more detail what I’m talking about: http://www.marvistavet.com/html/body_splenic_masses.html. The most telling quote for me in this article is this: “[If the dog has a splenic mass and you choose not to remove the spleen], eventually the dog will have a bleed from which he cannot recover.”

So what’s my point? Dogs die from splenic masses, often unnecessarily. It doesn’t matter whether they are malignant or benign. Sure, malignant masses affect other organs and the dog will eventually die anyway. But benign doesn’t mean harmless, it just means non-cancerous – benign tumors can still grow like crazy and rupture. In fact, I learned a parodoxical reality: the larger the splenic mass, the more likely it is benign because the dogs don’t survive the malignant ones long enough for them to grow large. Regardless of size or type, ALL splenic masses have the potential to rupture and cause death from hemorrhage. They are ticking time bombs, pure and simple. Isn’t it time we acknowledge this fact and start preemptively screening for the problem?

Lessons learned:

  1. Splenic nodules do not just disappear. I don’t know where Jasmine’s were in June 2009, but I’m sure now that they were lurking somewhere.
  2. Splenic nodules transform, and nothing good comes from that transformation. Even if they transform into benign masses, they can still rupture and cause catastrophic hemorrhage.
  3. If at all financially-feasible, we should consider doing annual diagnostic ultrasounds on our aging dogs to avoid these tragedies. They are non-invasive and require only a mild sedative (if even that).

I have a mammogram every year, and I’m going to do my best to ensure that my older dogs get the same consideration.

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.

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.