lumps on a dog

Dog Parent Guide to Lumps on a Dog

What to do about lumps on a dog

In the past 27 years, I’ve discovered dozens of lumps on a dog. Perhaps one day you are sitting around petting your dog as your fingers glide over a lumpy spot. You might be tempted to dismiss it as a bug bite or harmless wart but I’d ask you to go one step further: Have your vet assess it. Take a photo, mark it on a chart, and document it in your dog’s journal. Don’t wait, aspirate in most cases.

Lumps on a dog can range be any number of things, some of which include a lipoma, abscess, cutaneous histiocytoma, sebaceous cyst, melanoma, hematoma, basal cell tumor, mast cell tumor, plasmacytoma, fibroma, papilloma, or any number of things. Oncologist Dr. Sue Ettinger shared at the Fetch DVM360 2020 Conference,” I can’t look at a mass and know what it is and you can’t look at a mass and know what it is.” Dr. Ettinger recommends all her clients perform a monthly lump exam and we recommend dog parents perform 10 touches a week to be sure there are no new growths or changes in any lumps or bumps.

When a tiny raised lump appeared on my Cocker Spaniel’s shoulder blade about two weeks after getting her then yearly vaccinations, I felt a twinge of “something isn’t right” course through my veins. But I waited – after all a raised, small but swollen area at the site of vaccination is common, according to the veterinary literature I read. (at the time that didn’t mean Internet, it meant the UC Davis Book of Dogs). My dog’s veterinarian at the time tried to “squeeze” the lump and said it was probably nothing more than a pimple. That was back in the 1990s. He was wrong. The lump ended up growing in a few days, bleeding and was removed by an emergency veterinarian who diagnosed my dog with stage 2 mast cell cancer.

The C Word. You could have knocked me over with a pin.

You cannot tell what a lump is by visually inspecting it. Unless you have a superpower greater than Superman, a fine-needle aspiration or biopsy is needed in order to properly diagnose lumps on a dog. You may not even know that your dog has a lump, which is why home touching and examinations by the veterinarian are necessary and potentially life-saving.

What To Do About Lumps On A Dog

If a lump or bump appears on your dog, there are a series of steps to take. I will outline these steps below and also include a handy printable diagram to document lumps on a dog that you can pin to your bulletin board or hang on the refrigerator.

1) Do not panic: Easier said than done. Since my last Cocker Spaniel had cancer from a seemingly innocuous lump, I do react and do not wait unless said lump is an obvious bug bite. Take a peek at these dogs lumps in the photos below and see if you can decide which lump is canine cancer and which ones are benign. The answers will be provided at the bottom of this post with the printables.

Cocker Spaniels and other breeds tend to get more lumps and bumps on their skin because they have more sebaceous oil overall. Like people, dogs suffer from reactions to overvaccination and the use of too many chemicals, including topical flea and tick preventatives. I am not anti-vaccine, but I am anti overvaccination. The mast cell tumor found on my first Cocker Spaniel was a side effect from yearly vaccinations. The actual site of injection is where the mast cell tumor occurred, so you can understand my apprehension. I know better these days, so I do better for my dogs these days.

2) Aspirate or biopsy the lump: I am of the “don’t wait, aspirate” ilk. As Dr. Ettinger says, you can’t know what a lump or bump on a dog is simply by looking at it. Veterinarians go to school and promise to do no harm. I have total respect for veterinarians who act on a lump and refuse to tell their clients the lump is an “old age wart.” Similarly, not every lump on a dog has to be removed. Some can be monitored and watched, others can be lasered off, and some can be frozen off. I’ve had lumps on a dog removed using various technologies and various methods over close to three decades. Not every lump needs to be removed.

If your veterinarian refuses to act on a lump or tells you the growth is benign, I would recommend a second opinion. No one has the superpower to discern a malignant lump from a benign one. Just recently my dog was diagnosed with a plasmacytoma on the inner flap of his ear. Treatment consisted of cryoprobe (freezing).

A friend’s dog was going through the same diagnosis with a lump on her dog, but the plasmacytoma was on his gumline. He required extensive surgery under anesthesia and inner organ aspiration to be sure there was no spread of cancerous cells.

Read our journey here and why some dogs need surgery for lumps and others do not when it comes to plasmacytomas.

Here’s Dr. Ettinger performed a fine-needle aspiration on a Golden Retriever’s lymph node in the office:

Fine-needle aspiration is a simple test, the dog only feels the gentle prick of the needle (if anything), and no anesthesia is required. A thin needle is gently inserted into the lump. Fluid within the lump is drawn up into a syringe and then the veterinarian can assess it. Our veterinarian would look at the slide in his office for a first glance and to ease our minds. The pathology is then sent out and assessed at a laboratory. This is a first line of screening for most lumps and depending on the results, the pet parent knows how to respond. If mast cell is suspected, a veterinarian will usually give the dog an injection of Bendryl antihistamine first to ward off any mast cells in the bloodstream.

What to do if you find a lump on your dog

Pros and Cons of Fine Needle Aspiration Of Dog Lumps


  • It takes minutes to complete
  • No anesthesia involved
  • No sedation or in-clinic stay overs


  • A fine-needle aspiration (FNA) cannot discern if cancer cells have moved to cells or other areas of the body. So if the FNA comes back as cancerous or malignant or suspicious, more testing/procedures will be needed.
  • Sometimes the results are inconclusive:  Maybe there are not enough cells for accurate pathology reporting.
  • There can be a false positive with an FNA or an incorrect diagnosis.

Fine Needle Aspiration Concerns

There is a school of thought that sticking a needle into a potentially cancerous tumor can actually spread the disease.

“For tumors under the skin, or in the skin, the benefit of a diagnosis far outweighs cancer spread risk,” says Demian Dressler, DVM on his Dog Cancer Blog.  Fine needle aspirate is almost always a good idea.”

Dressler says that at this time, there is not enough data to suggest that in the dog doing surgical biopsies causes distant spread of cancers. This may change later, time will tell. There are some tumors in other species where biopsy does increase tumor spread odds, but very slightly.

For me, I err on the side of doing the aspirate and will continue to do so, especially for a lump on a dog.

At the vet’s office waiting for testing to begin.

How To Manage A Dog With Lumps

Do not attempt to squeeze or pop the lump unless you have a directive from the veterinarian to do so. For example, sometimes a sebaceous cyst will respond to warm compresses, but a veterinarian should direct you on if the lump is a benign cyst and how to manage it. Squeezing or attempting to treat a lump on your own can lead to infection and dogs can get very sick, especially if the infection enters their bloodstream.

If pathology determines the lump is benign, and most end up being benign, you need to monitor it. Photograph each new lump and keep the image safe and secure. Be sure to note EXACTLY where it is located on the dog’s body. When you write “ear,” that might not make a lot of sense if more lumps develop. I like to photograph my dog’s lumps and make a chart that shows the exact location of the lump. My vet measures each lump with calipers. Speaking of calipers…

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Invest in digital calipers or manual calipers. I got mine at on Amazon. They are accurate if used correctly. The human eye cannot discern whether a lump increased in size ever so slightly. Calipers minutely measure the width of a lump. Document it in your dog’s notebook. Write it down or even better, take a photo of the location and print that photo for your dog’s wellness book. Monitor the lump for any sign of growth or physical change. See the veterinarian. Your dog’s veterinarian should be measuring the lump in-office with calipers as well. Our dog’s veterinarian does this for every lump and bump on my dog.

Understand that some breeds (Akita, Poodle, Cocker Spaniel) produce more sebaceous oil in their skin, and therefore they may produce more lumps and bumps.

Malignant diagnosis: If a malignancy is confirmed, your dog’s veterinarian will discuss any number of next steps with you. In most cases, the lump will need to be removed. Factors such as age, overall health, chemotherapy and/or radiation if needed, and tumor location will need to be considered.

Guess Which Dog Lump Is Cancer

See if you can determine which of the following lumps are benign and which are cancerous.

lumps on a dog
lump on a dog's skin
ear lumps on my dog
growth on a dog's gums
lumps on a dog
lumps on a dog mouth
lump on roof of a dog's mouth
canine lumps and bumps

The first image is a benign lipoma on my dog, Dexter, that we are monitoring. The diagnosis was made with in-office fine-needle aspiration.

The second picture is of a dog with panniculitis. Not sure what that is? Read here about panniculitis and one woman’s journey through it with her dog.

The third photo is a plasmacytoma lump on my dog’s inner ear pinna that was diagnosed this summer and treated. Read more about dog plasmacytomas here.

The fourth photo is a puppy wart on the gum of a Cocker Spaniel. Dogs with warts are contagious to other dogs, but not to other animals or people.

The fifth photo is mast cell cancer of the skin, stage 3. It is malignant. You would not know this by simply looking at it.

The sixth photo of a dog with a lump reveals a plasmacytoma. Woody’s plasmacytoma had to be surgically excised.

The seventh photo of a lump on a dog is an actual image of the roof of my dog’s mouth. I was very concerned when I saw this lump. He was sitting on my chest with a bone in his mouth and I had my phone next me and managed to snap a photo. This is called an incisive papillae and all dogs have them. Some lumps in this location can be dangerous but this particular one was concerned by the veterinarian to be an incisive papillae. Dogs have them as part of their olfactory system and it is sometimes called Jacobson’s organ.

The eighth collage of lumps on a dog shows variations of growths and what they might be. Because cancer can look seemingly harmless, every lump and bump on your dog should be documented and examined by your vet with fine-needle aspiration or biopsy.

Where To Touch Your Dog For Lumps and Bumps

I recommend every dog parent touch their dog on at least a weekly basis. I feel my dog head to tail and underneath at least once a day. This is a good way to find any ticks, critters, or fleas that are hitching a ride on your dog, too.

Get to know where your dog’s lymph nodes are. If you know what normal feels like you will know what abnormal is if and when there are changes. Here’s a chart of the canine lymph nodes:

dog lymph nodes

Dedicated dog mom Nancy B., regularly runs her fingers through her Cocker Spaniel’s coat. She touches his skin and ensures to examine his body, armpits, belly, and gives him a thorough scan with fingers and eyes. Of course, her dog, Mayor, thinks he is getting a puppy massage. Thank goodness for Nancy’s due diligence: Twice she found small lumps on her dog and twice they have been removed. Both times, mast cell cancer was the diagnosis. Mayor has been given a stage 2 so now they must seek the help of a veterinary oncologist. He has had two lumps appear on the skin within months of each other.

Cute cocker spaniel with stage II mast cell cancer
Mayor has a dedicated dog mom.

Should Benign Dog Lumps Be Removed?

Yes, sometimes. Dr. Karen Becker recommends, “The only reason other than cancer that I recommend surgery for lumps or bumps is if the patient’s quality of life is compromised. For example, skin tags that grow on the margins of a dog’s or cat’s eyes are entirely benign, but because they are on the eyelid, as the pet blinks it can cause corneal irritation and pain. In a situation like that, even though the mass is not cancerous, I do recommend surgical removal because it’s causing the animal discomfort.”

Also warts may cause itchiness and a dog may lick or bite at them. Even though the wart is harmless and benign, if it becomes bothersome to the dog, it should likely be removed.

Sometimes a dog with a weak immune system may develop lumps or any number of health conditions, but there are things you can do in conjunction with the veterinarian to help strengthen your dog’s immune system, which I wrote about.

How Can A Dog’s Immune System Become Compromised?

  • Poor diet. A high-quality diet is imperative. Garbage in, garbage out.
  • Sugars and dyes and artificial colorings.
  • Genetically modified organisms in the diet (GMOs).
  • Over vaccination/adverse reactions to vaccines: Read here for the reality of dogs and vaccines.
  • Chemical-based topical treatments and preventatives for fleas and ticks. Use safer flea and tick preventatives, as we do.
  • Poor quality shampoos and skin treatments/conditioners: Shampoos can harm your dog: Be aware.
  • Household cleaners. I am very careful about whatever I use in my house and especially any place my dog walks. We have been using the Clean And Green Line for over a decade.
  • Pesticides, walking on chemically treated lawns, roads, and sidewalks with ice salt/chemicals.
  • And the list goes on: Very much like people, dogs react to their environment: Both externally and what we put into their bodies.

Can Dog Lumps and Bumps Be Prevented?

According to Dogs Naturally magazine, statistics show that 1.7 million dogs in the United States are treated for lipomas every year. WOW! Some experts believe that lipomas and associated fatty tumors are the body’s way of ridding itself of toxins and other unwanted materials. These growths, they say, are a sign of an underlying issue and are not acute.

Some things you can do to prevent lumps and bumps as best as can be expected – keeping in mind that sometimes even the most well-cared for dogs can and do develop lumps in their lifetime.

1.Feed a healthy diet. A healthy diet running on the front of a bag of dog food does not mean the dog who eats that food will be healthy. Know how to read a dog food label. Want to know what I feed my dog? Click here for my dog’s healthy diet.

2. Ensure your dog drinks a good supply of clean, filtered water daily.

3. Avoid over-vaccination. I am not anti-vaccine: I am anti over vaccine. Read here as to why.

4. Maintain a healthy weight: Overweight dogs, like overweight people, tend to have more health issues.

5. To prevent sebaceous cysts, try to keep your dog well groomed and brushed: Stimulating the oil gland and hair follicles helps keep oil from building up. I give my dog essential fatty acids in his diet and supplement with omega 3 in the form of fish oil. I rotate with organic coconut oil to help maintain a healthy overall sense of well being.

6. Maintain a clean air quality and do not smoke around your dog. Second- hand smoke isn’t healthy for any family member: Human or pet. We run an air purifier year-round in our household for a cleaner quality of air. We are not smokers. Once you see the filters after a few months, you (and your lungs) will be grateful.

My first Cocker Spaniel had several sebaceous cysts throughout her life. They burst and were subsequently removed under twilight anesthesia. She was a puppy mill rescue dog and had a multitude of health problems, and we loved her heart and soul. She had a number of immune system issues as she aged and a weakened immune system leaves the dog’s body prone to infection and illness.

Here are two images of sebaceous cysts. The first one is of a dog who had a sebaceous cyst that burst. She was subsequently seen by a veterinarian and sent home on antibiotics. The second photo is a canine sebaceous cyst in its early stages that eventually had to be surgically removed.

For More Information On Lumps On A Dog

Handy printable diagrams to document lumps on a dog

What Are Dog Plasmacytomas And How Are They Treated?

How To Treat And Prevent Lipomas in Dogs

Unexpected Warning Signs of Dog Cancer

Your Turn

Has your dog ever developed a lump or bump? How was it treated? Let us know in the comments below.