August 21, 2020 5 min read

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As a pet owner, it’s best to know when to take your pup to see his veterinarian. Semi-annual visits are always important so that preventive care and medical concerns can be addressed in a timely manner.

In between visits, your vet will rely on you to check in on your dog often. Issues like vomiting and diarrhea are just a few of the concerns that need to be addressed in a 24 to 48-hour window. But what about skin problems like lumps and bumps? What can you do to help, and when should they be evaluated?  

Should I worry about lumps on my dog?

In short, every new lump or bump should be evaluated by your veterinarian. Very small bumps that appear on the skin can be easily treated if they are hives or signs of a skin infection. Single or solitary lumps and bumps can be cysts or tumors, some benign while others are malignant and dangerous, and they can appear almost anywhere on your dog’s body.

Lumps that arebenign are the kind that has little to no impact on your dog’s overall health. Benign tumors, while technically a type of cancer, do not carry the risk of spreading to other parts of the body. If the tumor needs to be removed, then surgery is almost always curative.

Malignant tumors are a type of cancer that canmetastasize or spread to other body parts, resulting in disease and eventually multi-organ shutdown. These types of tumors must be dealt with quickly because surgical removal might not be curative if the tumor becomes too large to remove completely.

Even if you or your veterinarian suspect that a lump is benign based on outer appearance, cancer specialists recommend that all lumps bigger than one centimeter in diameter should be tested. A fine needle aspirate is when your vet uses a small needle to collect a cell sample from the tumor in question. These can often yield accurate test results. However, if a tumor does not provide an adequate cell sample, then a biopsy is necessary. This requires collecting a larger sample of the tumor itself, or sometimes it involves the removal of the entire tumor. Sedation or anesthesia is necessary to facilitate tumor biopsies.

What kind of lumps can appear on a dog?

There are many different kinds of lumps that dogs can develop. Some can occur in places that aren’t obvious like inside the chest or abdomen, and others can cause visual changes. Bony tumors may start out as having slight swelling in places, and skin tumors are probably the most obvious.

Lipomas are tumors that form fromadipose or fatty tissue. These are one of the most common tumors that can form in dogs. Middle-aged and older dogs are more likely to develop them, and lipomas are a benign type of growth. These typically appear as soft, movable, and well-demarcated subcutaneous tumors. Surgery is only necessary if the growth is in a problematic area or if it becomes too big for your pup to move or rest comfortably. A small subset of these can be malignant (liposarcomas) and so testing is necessary for confirmation.

Dogs can develop warts as well. These are typically caused by a papilloma virus which is not transmissible to humans, and they can occur in dogs of all ages. Warts are especially common in young dogs because of their weakened immune systems. Papillomatous warts may occur around the eyes, mouth, genitals, or other parts of the body. Many will regress after one to two months but some may require surgery to remove them, especially if there are too many or if any become ulcerated and infected.

Sebaceous cysts originate from your dog’s hair follicles. Because they affect the oil-secreting glands in your dog’s skin, many of them secrete a white liquid or waxy debris that almost has a “whitehead” appearance. They can rupture and become infected. Like many other types of skin cysts, these are benign and surgical removal is highly curative.

If you’ve heard of the term hemangiosarcoma, you might think of how this kind of tumor affects internal organs like the liver, heart, and spleen in dogs. When dealing withcutaneoushemangiosarcomas, they are less aggressive. It is true that they have the possibility to metastasize, but the risk is much lower compared to its internally-located cousin. Cutaneous hemangiosarcomas look like purple-colored blood blisters that can open and bleed. Surgical removal is also curative.

Mast cell tumors are one of the worst types of bumps that your pup can develop. They usually have around, reddened, smooth appearance and occur on top of the skin (dermally) instead of below the skin (subcutaneously). However, mast cell tumors are also referred to as “great pretenders” because they can look like many of the benign growths mentioned above. Mast cell tumors have a very high risk of metastasis, which is why early testing is critical. Deep and wide surgical margins are necessary for treatment, but if these margins are not achievable (e.g. around tight areas like the limbs or around the head), then additional therapies like chemotherapy and radiation will be necessary for treatment.

Further concerns

Veterinary cancer specialists recommend checking your pet for lumps and bumps at least once a week. This involves placing your hands on him and feeling around. Your pup might think of it as a nice massage as you check him out!

If you find a new bump, make note of it and schedule an appointment with your vet within the next week or so. If the bump seems to be bothering your dog (i.e. he is licking or chewing it), he should be seen within the next few days. Try to avoid squeezing or scrubbing the bump in case it should become infected or inflamed. You can also take a picture of it so that you can be more aware of any size or shape changes.


The uncertainty that comes with a new lump or bump can be scary. There is always the risk of something serious, and early detection is your best bet to protect your furry friend. Keep in mind that many bumps are benign and do not require aggressive therapy. Get to your vet as soon as possible for your pet’s safety and for your peace of mind!


Meet The Author

Dr. Erica Irish author of when should I worry about lumps on my dog

Dr. Erica Irish

Erica has worked in the veterinary field since 2006, starting out as a veterinary technician before graduating from the UF College of Veterinary Medicine in 2013. As a general practitioner in an animal hospital, she has many interests and is especially interested in dermatology, cardiology, internal and integrative medicine.

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