Found a lump on your cat?

black cat on white background


We know how worrying it can be to find a lump on your cat, cancer often jumps to mind. It’s important to remember that lumps aren’t always nasty, they can be benign (non-cancerous) or malignant (cancerous).

Always have new lumps checked by your vet and continue monitoring them for changes. If your cat has a lump (even if it is cancerous), there are often many treatment options available.


Many lumps, cancerous or not, look similar to the naked eye. Your vet might be able to tell a little bit based on how it looks, how quickly it’s growing and where it is on the body. To find out exactly what it is, your vet might decide to take a sample.

Benign lumps

  • Benign lumps are not cancerous. They are an overgrowth of cells.
  • They don’t spread around the body.
  • They can sometimes cause problems when they get in the way of other parts of the body (e.g. a big benign lump next to a leg might get in the way and cause pain when your cat is walking).

Malignant lumps

  • Malignant lumps are cancerous, they tend to spread around the body and grow more quickly than benign lumps.

You can read articles on the below for more information about lumps and tumours in specific areas of the body.

  • Skin lumps
  • Ear lumps
  • Tumours inside the tummy (including spleen, liver, kidney, stomach, gut, ovary and womb tumours)
  • Mammary (breast tissue) tumours
  • Brain and spinal tumours
  • Tumours inside the chest (including heart tumours, lung tumours and thyroid tumours)
  • Bone tumours.

When to contact your vet

Contact your vet if you find a lump on your cat. Every new lump should be checked. If the lump isn’t removed, you should monitor it closely and get your cat checked by a vet again if it changes (e.g. grows, changes in texture, starts to bleed or becomes painful).

You know your cat best. If you are concerned about them it’s always best to contact your vet.

Do I need to have every new lump checked?

Every new lump should be checked, even if your cat already has lots of lumps. Each one has the potential to be different from the last one.

Once your cat’s lump has been checked by your vet you should continue monitoring it.


Treatment varies depending on the type of lump and can include:


  • Some lumps don’t need treatment, just monitoring. Your cat should be checked at least once a year or more often if your vet decides.


  • Surgery may be necessary to take a sample from a lump or to remove it completely.
  • If the lump is in a position that makes it tricky to remove, your cat may need treatment at a specialist veterinary hospital.
  • In some cases, surgery may not be the best option and medication may be recommended first.


  • Chemotherapy are a group of medications are used to try to get rid of a cancer, slow it down or send it into remission.
  • Cats having chemotherapy need regular blood tests and check-ups to make sure they stay happy and without side effects during treatment.
  • In some cases, chemotherapy may be used to control symptoms only. This means that the aim is not to get rid of the cancer, but make your cat feel better for as long as possible.

Palliative medication

  • If the cancer is not treatable, medication may be given to make your cat feel better and give them a good quality of life for as long as possible.


  • Radiotherapy is a treatment that kills cancer cells with radiation. It is currently only available at a few specialist veterinary hospitals in the UK.

Removal or not?

Your vet may recommend removing your cat’s lump if it is cancerous, or benign but causing other problems.

If a lump is slow growing, benign and causing no problems your vet may recommend leaving it where it is. Similarly, if the risks of surgery are very high or if your cat has an advanced cancer it may be more sensible to leave the lump alone.

Monitoring lumps

If your vet asks you to monitor your cat’s lump at home, keep an eye on:

  • Size
  • Texture (one big lump or lots of little lumps)
  • Consistency (hard or soft)
  • Pain
  • Discharge (bleeding or weeping).

Taking photographs and measuring the lump every couple of months will mean you notice if your cat’s lump grows quickly or changes.

Illustration on how to measure a cat's lump

Measure your cat’s lump(s) every couple of weeks – keep a record.

How will I know if there is a tumour inside my cat?

Lumps on the surface are easy to spot, but lumps inside are much more difficult. Annual vet check-ups will help catch problems early.

Tumours inside your cat can cause a range of symptoms, which is why it’s important to contact your vet if you notice any changes in your cat’s health.


Treatment for a poorly pet can become very expensive. Consider insuring your cat as soon as you get them, before any signs of illness. This will ensure you have the support you need to care for them.

It’s also very important to speak openly with your vet about finances and cost of treatment as well as what you think is right for your cat. There are several treatment options and if one doesn’t work for you and your family then the vet will often be able to offer another.

Published: September 2018

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Written by vets and vet nurses. This advice is for UK pets only.

Illustrations by Samantha Elmhurst