Lump Check: When to Be Concerned About Your Cat's Health

Author: K. Marie Altoby K Marie Alto Updated 11 min read 2 Comments

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Nobody likes that heart-dropping feeling when you're running a hand along your fur baby's 🐈flank or spine or fuzzy little face, only to find a mysterious lump😲.

Maybe it's raised on the surface, or maybe it's deeper under the skin, and you need to poke and prod to really feel it out.

Whatever the case may be, it's a devastating thought😔, and our minds as pet parents immediately flash to all the horror stories 😱 and worst-case scenarios that could be coming. Is this it? The big one?

Truthfully, while it's never a good feeling, a mysterious lump isn't always a devastating illness.

There are plenty of reasons why a lump can form that can be easily treated or might not even need treatment, depending on its location and appearance.

So, if your cat 🐱 has developed a lump, how do you know if it's a bad thing or not? Let's run down some of the causes and treatment options.

This week’s educational video 🎥 is about cat lymphoma by Dr. Sue Ettinger 👩‍⚕️ a specialized cancer veterinarian. Lymphoma is one of the most common forms of cat cancer.

As with all things cats, for every pet parent, education is the first step. This video 🎥 is a must watch.

Always Call Your Vet

This will be short and sweet, every lump should be checked out by a professional.

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Even if you think you know what it is, pet health is full of similar-presenting ailments that have vastly different contexts and repercussions. It's always important to get any lump checked out, and old lumps should be monitored.

Now, will you need a trip to the emergency vet? Probably not.

Even the worst lumps tend to not grow so quickly that a matter of days makes a difference. The exception is if there are other signs that your cat's health is failing, like lethargy, lack of appetite, hindered mobility, or if the lump is characteristic of something like an infection and abscess, which needs to be treated immediately.

The best first step when you notice a lump is to call your vet.

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They can ask some questions about the lump and your cat's behavior, and help you determine whether you should bring them in immediately or schedule an appointment for some time in the next few days.

What a Lump Might Be

Now let's go through the options of what a lump might be.

Lumps can be caused by a lot of different things. Some of them are easily treatable, some are safe and can be ignored, and some are dangerous.

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Some might even go away on their own or with a simple treatment, while others won't. Here's a rundown of the kinds of things that can cause lumps.

Trauma. Have you ever bumped into something and had a bruise that wasn't just a tender spot but kind of tightened up and felt hard to the touch? That can happen in cats, too.

A trauma lump generally happens if your fur baby misses a jump and bangs into something, runs into something too hard, or is struck by something. They heal on their own, but they'll be tender, and you still might want to make sure your cat doesn't have internal injuries that need more treatment.

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Bites. Insect and parasite bites (like mosquitos, spiders, ants, fleas, insect stings, and so forth) will often leave a small, raised bump in the skin.

Most of the time, these are raised, reddish, irritated, potentially painful, and almost always really itchy. They'll also go away on their own, though if your cat has fleas, ticks, or other parasites, you need to get those treated first. You also need to make sure they aren't allergic to whatever got them.

Skin tags. A skin tag is just a small patch of skin that grows abnormally, but not in a cancerous way. They can be a little unsightly and, if they're in certain spots, can interfere with your cat's behavior, but 99% of the time, they're perfectly fine and ignorable.

They aren't painful, they aren't irritating, and the cat generally won't even pay attention to them. They also don't need to be removed unless, again, they end up disrupting your cat's behavior (such as if one grows too close to an eye and obstructs their vision.)

Abscesses. An abscess is a self-contained infection, usually caused by some kind of injury that gets infected. You can see them in infected teeth or where puncture wounds from other animal bites broke the skin.

They start small and invisible, but once they grow enough, the pus-filled abscess swells to the point that it causes pain, irritation, and more systemic effects of an infection like lethargy and fever. Abscesses need to be treated by a vet by draining them surgically and a course of antibiotics.

Cats who are allowed to freely roam outdoors are most at risk of cat fights, and the resulting bites and scratches and infections. Abscesses are painful, pus-filled swellings that can be associated with fever, lack of appetite, and depression, and need immediate veterinary attention.” - Dr Catherine Tiplady - RSPCA Pet Insurance

Cysts. Cysts are sacs of a tough material that fills with, usually fluid. They're often small and grow slowly, if at all, and they aren't painful or dangerous unless they're in a position that bothers your cat and hinders their behavior.

Most of the time, a cyst is ignorable, but if it grows too large or is positioned badly, it may need to be removed surgically. Draining a cyst is temporary; unless the full cyst, including the sac, is removed, it will fill back up over time.

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Note: two particular kinds of cysts can be more bothersome and require removal. Sebaceous adenomas are cysts caused by clogged and inflamed hair follicles and show up primarily on the head, but can be anywhere. Apocrine gland cystadenomatosis (try saying that three times fast) is dark-colored groups of cysts in the ear, which can be bothersome and need to be removed before they cause problems.

Granulomas. These bumps are usually circular and raised. They can appear anywhere on the body but are often seen on the lips. The exact cause isn’t well understood, but theories include some genetic predisposition and others suspect them to be caused by an allergic response.

Lipomas. A lipoma is a fatty growth that usually shows up under the skin. They are some of the most worrying because of how they're placed, but they're benign, slow-growing, and not painful or dangerous. Sometimes they may need to be removed if they might cause problems, but most of the time, they're fine.

Causes and Risks of Cat Lymphoma | Dr. Sue Ettinger | 11:34-Min Video

Warts. Also known as papillomas, are caused by a virus and are very rare in cats. They tend to only develop in very young, old, or immunosuppressed cats and may resolve on their own or need surgical removal. Something important to note is these are contagious to other cats.

Malignant tumors. This is the category broadly called "Cancer" and are, of course, the worst discoveries. Nearly 80% of all feline cancers fall into one of four categories, according to a study by the University of Missouri:

Cancers are the main reason why every lump needs to get checked out ASAP; they can move fast, spread throughout a body, and can end up deadly in a distressingly short amount of time.

It can happen to both young cats and older cats. Not all cancers are that aggressive, though, and many are treatable using modern surgical or medical techniques. It's critical to learn what you're dealing with to choose an appropriate treatment option.

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Of the common types of feline cancers, each one behaves differently.

Basal Cell Tumors

These are the most common and the good news is they tend to be solitary tumors that grow slowly. The best part is they are typically benign in cats, with only 10% classified as malignant.

They often need surgery and radiation or chemotherapy to handle. They're skin-level tumors and show up primarily around the head and neck.

Squamous Cell Tumors

These skin tumors are usually located in areas with no hair and occur more often in light colored or white cats.

“The ultraviolet radiation of the sun damages the cat’s DNA, and its cells begin dividing and multiplying. The tumors that result from solar exposure occur most commonly in lightly pigmented or white cats in areas that are hairless or sparsely haired.” – Dr. Margaret McEntee, DVM

These tumors grow slowly and can vary in appearance. While these tumors can turn deadly, when caught early there are several treatment options.

Mast Cell Tumors

These tumors are typically found on the head, neck, and legs. While they are typically skin-level tumors they can also grow in the respiratory and digestive tracts.

Some mast cell tumors can be surgically removed, but if they spread, they need more advanced treatment.


These tumors can show up anywhere in the body and they tend to be very aggressive. Depending on the location and whether or not it has spread will determine treatment options.

Often surgical removal will be the first line of attack with the potential for radiation and chemotherapy.

Note: Fibrosarcomas have been linked to certain vaccine injection sites. Because of the high potential to get the diseases the vaccines protect against, and the low incidence of developing a fibrosarcoma, vaccines are still recommended.

“The incidence of these tumors is not known, but is reported to be about 1 in 10,000.” – UC Davis Veterinary Medicine

Other kinds of cancers can cause lumps and bumps, but the above four are by far the most common.

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Identifying a Lump and Picking a Treatment

Early detection of any lumps and bumps can make a big difference in the success of any treatment. Establishing and keeping regular brushing and petting routines with your cat will go a long way.

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For cats, the best way to identify lumps and bumps is during brushing. Training your cat to tolerate things such as brushing as well as getting gently probed will ensure early detection of any abnormalities that might warrant attention.

You should get your cat used to you regularly touching and feeling specific areas including: the top of the head and down the cheeks, behind the ears, the chin and throat, the back and sides of the neck, the chest, the back, the stomach, around the groin, the armpits, the legs, the tops of the feet and between the toe beans.

When you find a lump, the first thing your vet is going to do is poke and prod at it to narrow it down. Sometimes, appearance alone can help identify it.

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Other times, the lump is in or under the skin, so things like the consistency and movement of the lump can help identify what it is. For example, is it growing in the skin or under it? Is it soft and feels full of liquid or is it solid?

If the vet thinks the lump is suspicious, the next step is usually cytology using a fine needle aspiration (FNA). A fine needle aspiration uses a tiny needle to extract some of the cells from the lump and uses both microscopy and chemical procedures called "staining" to identify what the cells in the lump are. It's all quite complex and very interesting if you're curious.

In some cases, this procedure alone won't identify the lump, and you may need a biopsy.

A biopsy will either remove the whole tumor or just remove part of it, depending on how large it is, and that tissue will be sent to pathology. This will then identify whatever the lump is and recommend any treatments necessary to make sure there's no systemic disease.

Possible Treatments and Follow-Up Care

Lumps in cats fall into a few simple treatment options.

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1. Watch and wait. If your veterinarian doesn’t think the lump looks suspicious, they will likely recommend you monitor it for any changes over time. Some lumps might just be a cosmetic issue, so if it isn’t causing problems or likely to grow, there is the possibility it can safely be ignored.

As with anything in medicine and veterinary, some veterinarians may disagree with a watch and wait approach.

Whenever I hear a new client says that her previous doctor recommended “waiting and watching” a tumor, my response tends to be: “Wait and watch what? The cancer spreading?” - Paws and Claws Animal Hospital – Holistic Pet Center

A cyst is a good example of something that might fall into this category.

Years ago, my sister’s cat had a cyst on the top of his head that was quite large. She had it removed but could have left it alone as it wasn't causing any long-term harm.

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Here is another case. Also many years ago, I was giving my angel Moosie some belly rubs when I felt a couple of lumps in his belly. As it turns out it was just fatty lumps and never needed any treatment.

Suffice it to say I’m not a vet or even a vet technician and I can only speak from my past experience. So, in my experience, a watch and wait approach has worked with my own cats and nephews.

My advice is that you use your best judgment. And when in doubt, just like you would do for yourself, get an opinion or second opinion from a professional.

2. They might need immediate treatment, including surgical draining or removal and antibiotics, as in the case of abscesses. They'll heal up once treated and won't reoccur.

3. They might need surgical removal. A simple surgical removal will cut out the lump and, if necessary, some amount of surrounding tissue to ensure all traces of the lump have been removed. Depending on the type of lump and whether or not there were clean margins, your veterinarian will determine if treatment can stop.

4. They might need a full course of cancer treatment, including surgical removal if possible, and a course of chemotherapy, radiation therapy, or a novel treatment option.

Depending on the age and health of your cat, your options may be limited.

Case in Point: My now angel Sosa had her first bump show up when she was around 16. Our vet didn’t even recommend aspirating it to determine what it was as her other health issues made her a poor candidate for any treatment options. She went on to fill our home with 3 more years of love.

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When to Worry

If a lump has appeared out of nowhere and is growing quickly, if it's painful and red, if it affects your fur baby's behavior, if it's bleeding or leaking fluid, or if your fur baby has previously been diagnosed with cancer, a lump is worrying.

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If, on the contrary it's small and isn't growing, not painful, and self-contained, take a deep breath, because it might be nothing.

No matter what the case may be, I cannot emphasize enough, you should always talk to your vet and get their opinion.

There's no real way to treat or even effectively diagnose most lumps from home, so you need veterinary care to ensure the best possible outcomes for your feline companion.

Keep in mind that benign tumors can turn into malignant ones.

“Even benign growths can turn cancerous, which is why it’s important to regularly check for masses on your pet and to let your vet know if anything has changed, even in a previously diagnosed benign growth.” - Jacksonville Community Pet Clinics

While most lumps can be handled and treated effectively, the sooner they're addressed, the better the outcomes.

If you have any non-medically-urgent questions about lumps on your cat, I'd be more than happy to help you out however I can. Just leave me a comment down below, and I'll get back to you as soon as possible. As a final reminder, though, if you have any worries about a lump, it's always best to talk to your vet first to see what they think.

K Marie Alto
K Marie Alto

K. Marie is an animal lover, wife, kitty mom, dog auntie, writer, and co-founder of Toe Beans, a proud American family-owned online boutique pet supplies store focused on the improvement of the life of furry family members via pet parent education, better products, and advocacy. She has over 20 years of experience as a pet momma. She loves sharing her personal journey and experience as a pet parent via her blog and Facebook page where she currently has more than 50K followers (@furrytoebeans) and counting :-). Read more

2 Responses


February 22, 2024

Hi Michael – Thanks for your question. A similar situation just happened to my nephew kitty. He had a benign cyst (monitored by his vet) on his neck that continued to grow over the years until one day it disappeared. Only a little scab remained and healed with no issues.

With that said, every lump and bump is different and should be looked at by a vet. A couple of low-cost options to consider include reaching out to your local animal shelter as some provide discounted services for those living within their community. You can also try a virtual vet consult to get their opinion. These online appointments are significantly cheaper than a regular in person vet appointment, but they are limited in their ability to assess your kitty through a webcam.

In the meantime, you’ll want to prevent your kitty from licking the area as it can cause irritation and prevent the skin from healing. Also continue to keep an eye on her to ensure her eating and litterbox habits haven’t changed, which could indicate a more serious issue.

Michael odett
Michael odett

February 22, 2024

My female cat had a little bump on her right leg that threw the years grew to the size of inch around yesterday day I was checking it and it was gone just a 1/2 inch red area today she has been licking it and now it’s a1inch circle and seems to be healing it’s not hurting her I have a very limited income is there something I could do at home please help
Thank you

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