Tumours and lumps

It's quite common for our pets to get lumps and bumps during their life. There are lots of possible causes, from bites, warts and infections to more serious conditions like tumours.

Here's our guide to some of the most common lumps and what to look out for.

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Should i get my pet's lump checked out by my vet?

Yes – you should always get any lump checked by your vet. Not all lumps are sinister and it’s probably nothing to worry about. However, it’s always best to have peace of mind and get them checked out early on.

Some lumps and bumps are more serious and need to quickly be seen by a vet.

Warning signs to look out for include:

  • Is the lump very large?
  • Did the lump appear suddenly?
  • Has there been a sudden change in the size of an old lump?
  • Has there been a change in feel or texture of an old lump – e.g. has a soft lump become hard, or less moveable?
  • Is the lump black or purple in colour?
  • Is your pet bothered by the lump – do they lick it or scratch it, or does it interfere with their daily life?
  • Does the lump look like an open sore (ulcerated)?
  • Is there any pus or discharge coming out of the lump?
  • Is your pet also showing any other signs of illness such as being sick, runny poo, going off their food, or just not acting like themselves?

If you spot any of these symptoms it’s best to get your pet to a vet as soon as possible. Even if you don’t see any of these, it’s still worth getting the lump checked out next time you’re at the vet.


Diagnosis: finding out what the lump is

Your vet will take a close look at any lumps and may also perform some tests. This could include test called a biopsy where a small amount of the lump is removed for testing. Depending on the results, your vet may recommend:

  • Waiting and watching. If it’s early days and there are no sudden changes, your vet might suggest waiting a week or two and seeing if the lump changes in any way. Taking photos or measurements every couple of days is a great way of keeping track of any changes. This doesn’t mean your pet isn’t getting treatment – it just means you vet doesn’t want to put them through a painful procedure if it’s not needed.
  • Treatment. Different treatment options may be available, depending on what the cause of the lump is. Your vet will talk you through all of the options and which approach they think is best for your pet.


Common lumps and bumps in pets

There are lots of different reasons to find lumps and bumps on your pet. Here are some of the most common and their possible treatments:


Fatty lumps (lipomas)

Lipomas are the most common types of lumps that pets get. They are harmless and are made up of fatty deposits. They can appear anywhere on your pet’s body, just under the skin. They are usually soft, movable and pain-free.

These lumps grow slowly and aren’t dangerous for your pet. Your vet will probably want to check the lump first and may test the lump by taking some cells from it with a needle. Usually, it is recommend to leave this type of lump alone. However, if the lump is getting in the way of your pet’s day-to-day life then your vet may think it is best to remove it e.g. if its irritating them or stopping them from moving normally.



Cysts (also called sebaceous cysts) are another common lump that can appear on our pets. They’re caused by the sebaceous gland, which contains oils which maintain your pet’s fur, getting clogged and forming sac-like growths under the skin. These clogged glands can then get infected and irritated. It might be a bit uncomfortable for your pet, depending where it is on their body. Some cysts burst and heal on their own but others might need to be drained or surgically removed by your vet.

Very rarely, a cyst can develop into a tumour so it’s best to get any cysts checked out by a vet.


Skin tags and warts

These are similar to the skin tags and warts that humans can get. They are generally harmless but can get quite large. Warts will usually disappear by themselves with time. If they are located around where your pet’s harness fits, or near a joint, then sometimes this can rub and cause irritation. If the wart or tag gets very big and irritated, or if it seems to be bothering your pet, then your vet might want to remove it.


Parasites and stings

Some lumps actually turn out to be the result of a parasite, such as a tick. Ticks can be removed using a special ‘tick hook’. Never try and pull the tick off without this, as part of the tick can become detached and burrow into the skin causing pain. It’s worth being aware of the signs of illnesses that are carried by ticks, such as Lyme disease, in case your pet has picked something up from their unwanted guest! Find out more about preventing ticks.

Bee and wasp stings can also cause raised bumps on your pet. They’re not normally dangerous unless:

  • Your pet has been stung on the face
  • Your pet has been stung near the nose or mouth (this could obstruct breathing, especially in flat faced breeds)
  • Your pet has been stung a lot of times
  • Your pet an allergy to stings

If you think your pet’s been stung and they’re having trouble breathing, ring your vet right away.


Blood blister

You might notice some swelling under the skin on your pet after some kind of minor injury, bite or scratch. These are often blood blisters. Also called haematomas, these are a blood-filled lump or bruise that is usually painful.

Blood blisters can get better on their own but they’re also painful for your pet. There could also be an underlying cause which needs treatment, such as an infection or parasite infestation. Book an appointment with your vet – they might recommend draining or surgically removing the blister.


Cat Bite Abscess

Cat bite wounds and abscesses can be a common problem. Cats often get into scraps, and they may get bitten as a result. Even unsuspecting dogs might get a nip.

A cat bite can cause nasty puncture wounds. Their teeth contain a lot of bacteria and when they bite, this puts the bacteria deep in the skin. A cat bite can actually be much more dangerous for infection than a dog bite. These types of bites can quite quickly grow into a serious infection. This will cause swelling, pain and even tiredness.

Animals with an abscess may worry or lick at the area and show other signs of being in pain. It can sometimes be hard to spot when a cat is in pain, but over-grooming an area, being protective of a certain area or not being as active as usual are all signs. Here are some common signs your cat has an abscess:

  • A puncture wound, followed by swelling over the next few days
  • The skin may look red, inflamed and sore (it may be difficult to spot this through their fur) or their may just be a tiny scab over the site of the swelling
  • Sometimes there will be a smelly discharge or oozing from the sore
  • The area might have a really bad smell
  • If it is on their leg then your cat may limp
  • Your cat may lose their appetite, seem quiet or less active
  • Your cat may develop a fever

It’s important to take your cat to the vet as soon as you notice any of these signs, or if you suspect your cat has been injured in a fight. Your vet will usually prescribe antibiotics and pain relief medication. They may also recommend that the abscess is surgically drained first, depending on how serious the injury is.

Untreated abscess can become very serious, and can even be fatal. So it’s really important to get veterinary care as soon as possible if you notice any problems.



Tumours are most owner’s biggest fear when they notice a lump on their pet. It’s important to remember that lots of tumours are not cancerous (these are called benign tumours), and won’t harm your pet’s health. Your vet might suggest you get a benign tumour removed if they interfere with your pet’s normal life e.g. they stop your pet from moving normally or cause irritation.

Sadly, it’s possible for pets to get cancerous (or malignant) tumours. These will often grow very quickly and can spread to other areas of the body (known as metastasizing). If your pet is diagnosed with cancer, your vet will talk you through the options available. This could include an operation to remove the tumour or treatments to kill the cancer cells, such as chemotherapy or radiation. These treatments are available for pets at some specialist vet centres.

We all love our pets and want to do everything we can to make them better but it’s important to think about the pros and cons of all treatment, especially something as serious as cancer treatment. Remember that your pet can’t understand what’s happening to them and some treatments can cause discomfort and pain. It is likely the treatment will be ongoing and not a one-off visit. If it’s likely the treatment will reduce their quality of life and won’t give them much chance of getting better, it might be kinder to put them to sleep. This is a difficult decision to make but your vet will be able to talk to you about what’s best for the health and welfare of your pet.

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