My Dog Has a Lump on His Skin. What Should I Do?

The day I found a lump on my cat Toby's jaw, my heart sank. Cancer, I thought. But the truth is, pets get many types of lumps and bumps that are benign or easily treatable. My pets have had lumps that turned out to be allergies, acne, fatty tumors and even -- on my cat Kura -- an inverted nipple.

The important thing is to talk to your vet. Together, you can decide which, if any, diagnostic tests to perform and what is the best treatment plan for your pet.

Here are a few lessons I've learned while going through the process with my own pets:

Get any lump or bump checked out by a vet. If it's malignant, catching a tumor as early as possible gives your pet the best shot at beating the cancer. If it's benign -- or something else entirely -- your vet may have suggestions for treating it and can offer advice on what to do if similar a lump appears again.

"A vet will want to know when you first noticed the mass, whether or not it is changing, and whether it's bothering your pet," veterinarian and Pawcurious blogger Dr. V tells us. "They will also want to know about any masses removed or biopsied in the past."

Expect tests. The truth is that no vet, no matter how skilled, can give you a conclusive diagnosis of a lump on your pet's skin without doing some kind of diagnostic test. "Kekoa [Dr. V's dog] had what I thought was a simple lipoma, a common benign fatty tumor," says Dr. V. "But I biopsied it just to be sure and it was an aggressive sarcoma. I'm so glad I did that!" More than a year after treatment, Kekoa has not had a recurrence of the cancer.

Ask questions about the test(s) your vet recommends. The questions you ask your vet can give you a good idea of what you may be dealing with and help you decide whether or not to request further tests. Here are a few that can help open up a dialog:

  • What kinds of lumps and bumps do you usually see in pets of this age?
  • What kinds of masses do you usually see in this spot on a pet's body?
  • Do you think any organs, bones or tissue are involved?
  • Are there any further tests you'd recommend?
  • Is my pet experiencing any pain?
  • What are the worst- and best-case scenarios?
  • If this were your pet, would you perform a biopsy? If so, which kind?
  • How accurate is the procedure you recommend?
  • Will having a clear diagnosis change the plan for treatment?

 

    Understand the different types of tests. A cautious vet will probably want to examine a piece of the lump under a microscope so he or she can see what types of cells are involved and if they are cancerous. Here are a few of the common ways your vet may collect a sample:

    • Microscope smears: If the mystery bump is oozing, fluid-filled, or your vet can otherwise get a sample of the mass easily, she may opt to dab a sterile microscope slide on the lump. As PetMD notes, a veterinary pathologist is most often the person who reviews the slide, but sometimes an attending veterinarian will make the diagnosis.
    • Fine-needle biopsies/aspirations: In a fine-needle biopsy, "a small needle is introduced into the mass, usually while the animal is awake, and some cells are removed," says Dr. V. "Usually this is a simple, minimally invasive procedure that doesn't require sedation. It is inexact compared to true biopsies, but as a starting point you can get some good information. I've diagnosed mast cell tumors, lymphoma, and various other serious cancers with this simple procedure."
    • Incision and/or punch biopsies: Depending on the placement of the mass, its size, shape and several other factors, your vet may recommend removing a small piece of the lump while your pet is under general anesthesia. In Toby's case, the vet needed to take a sample of the mass from inside his mouth -- and there was no way Toby was going to allow that while he was awake! Before putting your pet under, your vet may require blood work to make sure your pet is healthy enough to undergo anesthesia. She may also suggest taking an x-ray or a CT scan to get a better picture of the mass.
    • Excision biopsies: Excision biopsies involve removing the entire mass and examining it under a microscope. These procedures usually require general anesthesia and all the same pre-anesthesia diagnostics as incision biopsies. (In Toby's case, we took x-rays of his jaw and saw that the mass was attached to his jaw bone, making an excision biopsy dangerous and tricky.)

    Your vet will recommend the type of procedure based on a number of factors, including how long the lump has been there, its shape and size and whether there have been any recent changes.

    If your pet is already scheduled to undergo anesthesia for another procedure, an excision biopsy may be the cheapest option. But some masses need to be removed differently from others, so if you opt for an excision biopsy, be prepared for a second excision if the results determine that one is needed. "A good example of this is a mast cell tumor, which requires 3-cm. margins all around," says Dr. V. "That is a huge amount of tissue to need to remove, even for a small mass! If you were to do an excisional biopsy assuming it was something else, you might be looking at a second procedure to get surgical margins if the margins were not clean on pathology."

    Ask yourself how badly you need to know. This is a question only you can answer. Tests are expensive, anesthesia has its own risks and sometimes asking the questions above can give you a pretty good guess at what you're dealing with without performing diagnostics. Plus, in some cases, having a definitive diagnosis won't change your vet's recommended treatment plan. (One great way to avoid having to take cost into as much consideration is by having pet insurance.)

    With Toby, even before biopsy we were pretty certain he had an aggressive form of cancer that has few treatment options. But I knew that I'd always wonder if we'd missed something else -- something treatable -- if we chose not to do the tests. We did a biopsy and my worst nightmare was realized -- it was cancer. Still, the early diagnosis gave me a clear plan of action and helped his vet and me do everything we could to keep him comfortable. When Toby passed away earlier this year, I said goodbye knowing I'd done everything I could -- and that has helped immeasurably as I learn to live without him.