Everything You Need To Know About Lumps and Bumps

While you are petting or bathing your precious pet, cat or dog, you notice a lump on their side, leg, or head!  You have never noticed this bump before!  Is it nothing?  Is it cancer?  What do you do?

Most, if not all of us know somebody in our family or circle of friends who has cancer. It is a scary disease, because even though you can try and protect yourself as much as possible it can happen to anyone. Our beloved pets are no exception.

Prevention is always better than a cure and we have many imaging modalities and laboratory tests to try and catch this insidious, invasive, and often deadly disease as early as possible.

What Could My Pet’s Lump Be?

Lumps and bumps are relatively common presenting complaints for us vets and deciding what to do about them can be tricky. Although most lumps are harmless it is impossible to tell what sort of lump you are looking at. There are many different things that can cause swellings, such as bruising or fluid build-up, abscesses, things attached to the skin (eg. small parasites) and, of course, cancers. If you find any unusual lump or swelling on your pet, you should ask your veterinarian to check it out.

What Your Vet Considers When Examining a Lump

When you bring your pet to have his/her lump assessed, we will closely examine the lump, but also the rest of your pet in a full physical examination. This is important, and many questions will be going through the vet’s mind as he/she does this, such as:  How is this pet’s overall health? Does his/her heart seem healthy for potential anaesthetic? Are there any other “lumps” (masses) in his/her abdomen or elsewhere? Is there significant periodontal disease where a dental cleaning and lump removal could be considered concurrently (saving money and helping reduce the anaesthetic risk)? Is there evidence of a potential cancer spreading to the lymph nodes?

Simply put, a full physical exam is very important and gives us plenty of additional information. We may also recommend running some blood work or urinalysis, which can sometimes detect abnormalities caused by cancers. These tests are also beneficial in determining if your pet can safely undergo anaesthetic in the future to surgically remove the lump.

We cannot tell whether a lump is cancer or some other kind of swelling just by looking at it, so one of two options is generally recommended to better assess and deal with the lump. The first option is a Fine Needle Aspiration (FNA) and the second is an excisional biopsy. There are pros and cons to each option.

Pros and Cons of Using Fine Needle Aspiration

With a fine needle aspiration (FNA), we take a needle and basically poke the lump, trying to suck up some cells from it. We then squirt our sample onto a microscope slide and send this to a pathologist to examine. They then send us a report, usually within three to five days.

According to the American Veterinary Medical Association (AVMA), while an can provide basic information about the tumor type and identify certain types of cancer, a biopsy “is often necessary to confirm the diagnosis and help determine if the neoplasm (abnormal mass) is benign or malignant.”

Advantages of FNA’s: Disadvantages of FNA’s:
Relatively inexpensive Occasionally, but not commonly, the report comes back inconclusive, and the fine needle aspiration may need to be repeated or a biopsy performed
Usually gives us an answer as to what the lump is and how concerned we should be Takes a very tiny snapshot of a much bigger picture and we could potentially miss cancer cells (not 100% accurate test but usually pretty good)
Can be quickly done with minimal discomfort and restraint, during your appointment
If the lump is a cancer of some sort, it is better to know this BEFORE surgical removal, so that appropriate margins can be surgically excised to give the best chance for a cure
If no evidence of cancer is seen by the pathologist, surgery can be avoided, and the mass can be closely monitored. However, even if the lump is benign, we sometimes need to remove lumps if they continue to grow and physically inhibit your pet’s mobility

Pros and cons of a biopsy

Some pet owners prefer to skip this step and have the lump removed surgically from the get-go. In this case, the entire lump is sent to the pathologist. In human medicine, skin lumps are often removed by a doctor using local anaesthetic.

In veterinary medicine this method cannot be used because your pet must lie very still during the procedure to make sure that the entire lump is removed Even though the lump may be quite small, just one jump or move may mean the veterinarian could miss part of the lump, which could be quite dangerous for all concerned.

Yet again, there are pros and cons with excisional biopsies:

Advantages of excisional biopsies: Disadvantages of excisional biopsies:
Stands a good chance to remove (ideally cure) and diagnose the lump at the same time Considerably more expensive than cytology test
Saves expense of fine needle aspiration and cytology above Pet would have to come back at a later date, fasted for either sedation and/or full anaesthetic
More definitive answer as to what the lump is when the entire thing is excised and sent to the pathologist A second surgery may be required if insufficient margins are excised surrounding the lump at the initial surgery, and the lump is confirmed to be cancerous by a pathologist.
Though extreme caution and care is always taken with your pet at our clinic, there is obviously an increased risk of complication with your pet with anesthesia and surgery compared to a simple needle poke

In most cases, the treatment required for small growths is to remove them. However, if the cancer is malignant, your vet may want to make sure that there is no sign of spread and to do this they may need to take x-rays or perform an ultrasound examination.

Hopefully this gives you more insight into the options that exist for lumps, but regardless of the situation, an assessment and discussion with one of our veterinarians is always best in order to make the best plan for your pet.  As with our own healthcare and so many other health issues with our pets, early detection is best with regard to lumps and can certainly avoid future complications, large unnecessary expenses, and mortality.

Types of cancers:


Benign lumps may grow bigger, but do not spread elsewhere. Some growths can cause problems if they continue to grow, such as restricting movement or breathing due to the size of a lump.


Malignant lumps are aggressive lumps which grow and can spread through the body and can affect organs such as lungs and liver. Malignant growths must be removed before they spread elsewhere.

Most common tumours seen in dogs and cats

Lipomas or fatty lumps

This is probably the most common type of lump found on dogs, and is more common in overweight or obese pets. Lipomas can be found on any dog breed and can even be found on cats. These are generally benign cancers that can grow quite slowly and rarely spread. In some cases, they may need to be removed if they grow too large or inhibit your pet’s mobility.

Cancer – Mast cell tumours

Mast cell tumours are a type of cancer that can take on many different appearances. While some are harmless and cause no problems, others can be very dangerous and grow and spread very quickly. It is difficult to tell if and when they change from a benign cancer to a malignant cancer, so all mast cell tumours should be removed.

Breast cancer – Mammary tumours

Whilst some lumps in the mammary glands in female dogs can be quite harmless, others are amongst the most aggressive forms of cancer. In male pets, mammary lumps are often particularly nasty. In most cases, surgical removal of mammary lumps is advisable.


Warts are more common in older animals, but a certain variety can be seen in young puppies too. They may look like a small tag of skin attached to the coat. In some cases, they require removal if they become irritating, inflamed or infected.

Sebaceous cysts

These are swellings filled with a creamy substance that may be mistaken for pus. Often seen in older cats and dogs and found in the middle of the back. Sometimes the swellings become quite red and normally they do not cause any problems other than soreness.


Histiocytoma are red button like lumps that are usually found on young pets. They usually go away as rapidly as they appeared.

A final word on lumps and bumps

A watchful eye is rewarded. Noticing changes in your pet’s health, including the appearance of lumps and bumps on their coat, can lead to early diagnosis and successful treatment. Always check with your veterinarian if you notice any changes, or if you have any concerns about your pet’s well-being. Regular annual or semiannual exams with your veterinarian and monthly examinations at home can help you stay on top of any changes in your pet’s existing lumps and bumps—and quickly detect any new ones.

If you have any questions or concerns about lumps or bumps on your pets and live in the Calgary area, our vets would be happy to help.

Call us at 403-615-8016 to book an appointment for an examination and determine the best treatment plan.