Mack the Knife (Part 1)

( Warning: graphic medical images included in this post, please be advised. )

One of my favorite clients is an elderly woman we’ll call Mrs. B. She’s been coming to my practice for years. She started out with 20 cats. Slowly over time, her menagerie has gotten smaller and smaller, with cancer being the main culprit.

One of her remaining cats is a scraggly old male named Mack. Mack was taken off the street as a feral cat 17 years ago. You’d think, after 17 years, the cat would realize that Mrs. B was a friend and not a foe, but no, he hasn’t. Mrs. B hasn’t been able to touch this cat for 17 years. She never sees him. Occasionally, if she comes home and turns on the light fast enough, she’ll catch a glimpse of him as he scurries away like a cockroach. The only time she gets to touch him is when she brings him to see me. For that, she has to enlist the aid of a friend (who happens to have once been a veterinary technician). Trapping him and pushing him into a cat carrier is an ordeal, however, at 17 years of age, he’s lost much of his fighting spirit and he eventually yields to his pursuers.

Recently, on one of her rare glimpses of Mack, she noticed that he was limping on one of his front legs. Despite being three-legged lame, Mack put up a fuss about being corralled. When she finally brought him into me, it was clear that something was terribly wrong with Mack’s left front foot. A giant, unusual looking tumor.

As you can see in the photo, there’s a big pink tumor in the space between the main pad and toes. Further up the foot, there’s another pink fleshy tumor, surrounding the dewclaw. Interestingly, he had a similar looking fleshy mass in the middle of his back. 

I recommended that we remove and biopsy the mass on the back, and try to remove (and biopsy) the mass on the foot. Removing the mass on the back would be easy. There is a lot of skin in that area, and pulling the skin defect together with a few stitches would be no problem. The foot would be more of a challenge.

There’s no extra skin on the foot, so removal of skin in the foot area often leads to a defect that can be difficult to close. In Mack’s case, we didn’t have much of a choice. If unaddressed, this mass would continue to grow and become infected.

Removing the mass around the dewclaw wasn’t that bad. Surprisingly, I was able to pull the skin and close the defect without much tension on the skin. The foot paw itself was another matter. The mass was pretty infiltrative, and by the time I managed to get it all out, I was left with a large defect that would be a challenge to close.

The only way I could conceivably close this was to cut the webbing between toe #1 and toe #2, and then wrap the skin around each toe and suture it closed.

I was then able to wrap the remaining piece of skin around both toes #3 and 4, fusing them together. We then bandaged the foot and kept Mack hospitalized for a few days in our facility, so that we could change the bandage regularly and watch the foot.

Unfortunately, the biopsy came back as a mast cell tumor. These are mysterious tumors that occasionally arise in feline skin and are almost always benign. Removal is recommended, because they do have the theoretical potential to spread to internal organs like the spleen and the gastrointestinal tract. Mack’s mast cell tumor was different, though. His was a malignant mast cell tumor, and it had already spread to other parts of his body. In fact, the piece of tissue from his foot was identical, under the microscope, to the piece from the middle of the back. They were the same tumor, in different parts of the body, indicating metastasis (i.e. spreading).

Although euthanasia would be justified, especially in a case like Mack’s, where chemotherapy and regular checkups and monitoring wouldn’t be possible due to his feral nature, Mrs. B agreed to take Mack home, keep him in a cage so that he wouldn’t disappear for weeks at a time, and bring him back for us to check on his foot. I fully expected the foot to look terrible at the next visit, because I could not remove the entire tumor, and I expected it to grow back. To my surprise, the foot looked great!

The sutured toes were healing. Only the middle toe hadn’t healed.

I didn’t think it would, because it looked like the open area of the toe was infiltrated with tumor tissue, but at the next visit, you can see that it healed even further.

But, more trouble was in store for Mack. Stay tuned.


  1. One of my cats, Lucinda, had a mast cell tumor above her left eye in January of this year. But it started out 4 years ago as, what appeared to be a bug bite. Very tiny but she scratched it so I took her to the vet. It stayed 'bite size' until this past January when it grew bigger quickly. My vet removed it, sent it to The University of Tennessee, (I live in TN) and they were able to tell us what it was. I was told that these type of tumors are common in dogs but not so common in cats. So every week, I do a full body check on her to make sure nothing is hiding under all her fur! I took pictures of it, I felt sorry for her but I called her "Franken-kitty anyway!

  2. That is really cool! You really should add "feline plastic surgeon specialist" next to your name. Too bad I missed that surgery...Miss you all!


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