We’ve been there: Your pet seems fine, and then all of a sudden, a new lumpy, bumpy mass pops up on his body, seemingly overnight. Sometimes these lumps and bumps can be caused by wounds, but other times they can be warts or other types of growths. Whatever the reason for them, they’re among the top ten reasons owners head to the veterinary hospital.

And that’s a good thing, since sometimes, a simple swelling can be a sign of a dangerous but treatable disease. The only way to be sure is by going to your vet and letting them assess the new development.

Veterinarians often refer to superficial lumps and bumps as “masses.” Strictly speaking, they might also be legitimately called tumors or growths, even if they’re not cancerous. These words simply describe enlargements under or within the skin.

Most of the time the lumpy, bumpy mass is in or just under the skin or sometimes even in the mouth. Your veterinarian will need to differentiate these lumps from other masses, such as bony swellings and abdominal distention which are a different sort of thing.


Most superficial lumps and bumps are caused by one of the following:

1. Puncture wounds: These injuries — usually the result of bites from other animals — fester beneath the skin’s surface to form an abscess, swelling (sometimes tremendously) before eventually breaking open.

2. Benign masses: Warts, skin tags, fluid-filled cysts, fatty tumors (lipomas), and histiocytomas are all examples of benign (non-cancerous) masses that may or may not need to be removed.

3. Cancerous tumors: These are the scariest of the three culprits, because simple removal may not solve the problem. Cancerous tumors can spread — sometimes locally (to skin, fat, bone, or muscle next to the original lump) and sometimes to distant parts of the body.

What To Do At Home

Here are some simple actions you can take to help your pet heal:

1. Assess your pet. If he appears to be feeling well and if the mass isn’t red, painful, or giving off a strong odor, you’re likely not dealing with an emergency, but you should go ahead and make an appointment with the vet. If the pet is lethargic, has a poor appetite, or shows any other signs of illness, then your may be dealing with a more urgent situation.

2. Mark the mass. If the mass is small and hard to find, mark the hair immediately adjacent to it with an indelible marker or a tiny bit of nail polish to make it easy to find at the veterinary hospital. Smaller masses get “lost” every day.

What Your Veterinarian Will Do

It’s your veterinarian’s job to figure out the origin of the mass. To do so, he may take several of the following steps:

1. Ask about your pet’s history. Your pet’s doctor will probably ask evaluation questions such as, “When was the lump first noticed? How has it changed? How has your pet been otherwise?” and other questions to help determine the severity of the problem.

2. Perform a physical examination. The look and feel of a mass can offer a veterinarian plenty of information. But examining your pet from head to tail can be similarly beneficial and is therefore considered an essential step, even when investigating a seemingly simple skin tag.

3. Fine needle aspirate the lump. Inserting a needle into the mass is a very common practice. It’s done with the hope of extracting a few telltale cells that can be identified under the microscope. In the case of an abscess, the fine needle aspirate would typically identify the presence of a large “pocket” of pus. Sometimes, the microscope slides are sent to a diagnostic laboratory for further examination. Unfortunately, aspirating a lump only tells you what the cells look like in the spots accessed by a small needle. It can’t be 100 percent representative of every cell within the mass’s confines. That’s why your veterinarian may also recommend an incisional biopsy.

4. Perform an incisional biopsy. In this procedure, a small bit of the mass is sampled. The tissue sample is then submitted to a diagnostic laboratory for examination. Your veterinarian will choose one of several methods for obtaining the tissue sample, but your pet will likely need to be sedated or anesthetized briefly for this approach.

5. Perform an excisional biopsy. This method increases the chances of making a definitive diagnosis, because it involves removing the entire lump (at least what the veterinarian can see and feel) and submitting the tissue to a diagnostic laboratory for examination.

If a diagnosis can be confirmed, your veterinarian can give you the most accurate information about prognosis (what to expect long-term for your pet) and treatment.


Treatment depends on the underlying cause and will range from no intervention to minor surgery to something much more involved if the lumps or bumps are caused by a serious medical condition, such as cancer.

This article was written by a Veterinarian.