One of the reasons that I (Perry Jamison) love my job is that almost everybody you meet (outside of work) has or has had a pet.
Whenever someone asks what I do for a living and I say that I am a veterinarian, it is inevitable what will follow. People always ask about their pets.
If their pet is with them, they will commonly show me the animal and ask, “What do you think this mass is and should I worry about it?”
Often, I will examine the area and give my best guess as to what it might be; however, I do not like to guess and there is a logical way to go about determining what has caused the lump and if we should be worried about it.
The first question to consider is should we be concerned about every lump and bump on our pets?
Most are going to be benign growths that are only aesthetic concerns and will not affect the quality or longevity of their lives.
Unfortunately, until you know what the mass is made of, you cannot know this for sure. For this reason every lump should be brought to your veterinarian’s attention.
There are some types of growths that many veterinarians may be able to feel comfortable diagnosing visually. These are skin growths or eyelid growths.
Visual inspection is not a definitive way to diagnose what a mass is, but it does provide significant information.
Similar to a human dermatologist, in veterinary medicine we document the location and size of the mass using a body map.
Our images are of a dog or a cat (top, bottom, right side and left side) and the location of every lump and its size can be marked on this map. This way, it is easy to note any changes over time.
For the vast majority of lumps and bumps, obtaining a cell sample for evaluation is the next step.
As in human medicine, there are veterinarians who have received advanced training in assessing microscopic cell samples from animals. A veterinary pathologist can look at cells from the mass under a microscope to get a definitive answer as whether this is something to worry about or not. There are two ways for your veterinarian to obtain samples each with advantages and disadvantages.
The most benign cell sampling technique is the fine-needle aspiration. As the name implies, this is where a small needle is inserted into the mass and a tiny cell sample is obtained. A syringe of air is used to push the sample out of the syringe and onto a glass slide for submission to a pathologist. This technique can be used on masses outside the body and along with ultrasound guidance to obtain samples from masses inside the body as well.
There are several advantages to the fine-needle aspiration. The procedure causes minimal discomfort since a small needle is used. In most patients, sedation is not needed thereby eliminating the associated risks and allowing the patient to go home immediately.
At the laboratory, there is very little processing that needs to be done for the pathologist to assess the sample, which speeds up how quickly results return.
The major disadvantage to the process is that the sample size is small, which can sometimes prevents the pathologist from giving us a definitive answer. Another rare complication is the potential for bleeding. This is a risk any time a needle is inserted into any lump or mass, but fortunately this is extremely uncommon.
The other cell sampling technique is to obtain a biopsy. A biopsy is when a piece, or better yet, the entire mass, is removed and submitted for evaluation. The larger sample size allows the pathologist to look at not only the cells but also how they interact with each other.
If we give them a good sample, it is rare that the pathologist cannot give us a definitive answer. If the entire mass is removed, they can also look at the edges and insure we did not leave any tumor cells behind.
If tumor cells are still present at the margin of the sample, we can often go back surgically and resect the rest.
The major disadvantage of a biopsy is that it is more invasive and considered a surgical procedure. Anesthesia is routinely required and depending on the location and size of the growth, there may be some initial discomfort.
Another concern is that each tumor type behaves differently, so some require more aggressive removal than others. Without knowing the type of cells beforehand, we may not remove enough and we might have to go back for a second surgery.
Since biopsies are pieces of tissue, they must be cut into microscopically thin pieces for the pathologist to assess. This process takes several days, which is why it takes longer to get the results back from a biopsy when compared to a fine-needle aspirating.
With all that being said, every lump and bump on your pet should be assessed. Most will be found to be benign, such as the fatty tumors called lipomas, and you can stop worrying. If they are a form of cancer, however, the sooner a diagnosis is obtained and treatment started the better the prognosis.
Dr. Henri Bianucci and Dr. Perry Jameson are with Veterinary Specialty Care LLC. Send questions to firstname.lastname@example.org.