Lumps and Bumps and Tumours, Oh My!

Written by Dr. Sean Colyer

You’re petting your precious pet, cat or dog, and you notice a lump on his side, or maybe her leg, or his head!  You’ve never noticed that before!  Is it nothing?  It is cancer?  What do you do?!

Lumps and bumps are relatively common findings for us vets here at McLean’s, and deciding what to do about them can be a tricky situation.  True enough that many lumps on both dogs and cats are benign and not very worrisome; however no pet owner or veterinarian can simply look at or feel a lump and be able to discern these benign lumps from more worrisome ones.  We can speculate and discuss probabilities, but the reality is that some testing needs to be performed before anything can be safely considered benign. It is important and definitely recommended to have lumps assessed by a veterinarian, because even some lumps that look and seem benign can be worrisome cancers, and vice versa.

When you bring your pet to have his/her lump assessed, we’ll of course closely examine the lump, but also the rest of the pet.  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 anesthetic?  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)?  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.

Pertaining to the lump in particular, we generally recommend one of two options to better assess and deal with the lump:

  1. Fine needle aspiration and cytology
  2. Surgical removal

There are pros and cons to each option.  With a fine needle aspiration, we take a needle and basically poke the lump, trying to suck up cells from it.  We then squirt what we’ve collected onto a microscope slide, and send this to a pathologist (a scientist who specializes in disease).  They then send us a report, usually within 3 days.


–       Relatively inexpensive

–       Usually gives us an answer as to what the lump is and how concerned we should be.

–       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 of a cure

–       If no evidence of cancer is seen by the pathologist, surgery can be avoided and the mass can be closely monitored.  Even if benign however, we sometimes need to remove lumps if they continue to grow and physically inhibit your pet.


–       Occasionally but not commonly the report comes back inconclusive, the fine needle aspiration may need to be repeated or a biopsy performed

–       Taking a very tiny snapshot of a much bigger picture and we could potentially miss cancer cells (not 100% test but usually pretty good)

Some pet owners prefer to skip this step and have the lump removed surgically from the get-go, having the entire lump sent to the pathologist.  Yet again, there are pros and cons with this:


–       Stands a good chance to remove (ideally cure) and diagnose the lump at the same time

–       Saves expense of aspiration and cytology above

–       More definitive answer as to what the lump is when the entire thing is excised and sent to the pathologist


–       Considerably more expensive than cytology test

–       Pet would have to come back on a later date, fasted for either sedation and/or full anesthetic

–       The anesthetic and surgery may be stressful to the pet and potentially unnecessary

–       Though extreme caution and care is always taken with your pet at McLean’s, there is obviously an increased risk of complication with your pet with anesthesia and surgery compared to a simple needle poke

–       Insufficient margins may be surgically excised if the lump is a cancer and we don’t know that before the surgery, therefore a second surgery may be required if cancer is confirmed by the pathologist

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.

If you have any questions or concerns with your pet, please do not hesitate to call us at McLean Animal Hospital 416-752-5114.  We are here to help!