Bumps and Lumps On Cats

Bumps and Lumps On Cats

Sep 21, 2021
12 min

Lumps and bumps are very common among cats. Oftentimes, they are incidental findings when owners brush their pet’s hair coat. Some skin growths are slow-growing, while others seem to appear overnight. Some lumps on cats are growing on the skin surface, some within the skin itself, and others developing under the skin. Some tumors are painful and bothersome, others don’t bother the affected cats at all.



Lumps and bumps on the body of cats are NOT ALWAYS cancerous or malignant. This is a fact that cat parents should always remember. Finding one on your furball’s body can mean anything from an infection, a parasite, or more serious issues. Thus, for your peace of mind, you should make an appointment with your veterinarian so your cat can be given a thorough examination and possibly undergo some tests.


Malignant Lumps versus Benign Cat Tumors

Benign lumps


  • These are not cancerous.
  • They don’t metastasize or spread to other parts of the body.
  • Benign tumors that grow big may impede the movement of a body part or the cat’s mobility. In this case, your veterinarian may decide to have it removed by surgery.

Malignant lumps


  • These growths are cancerous.
  • They have the ability to spread to other parts of the body (metastasis).
  • Malignant tumors grow more quickly compared to benign lumps.


Common causes of skin lumps and bumps in cats

  • Trauma

A mild trauma or injury can cause a bump on the cat’s skin. A bump may heal without any medical intervention, but there are instances when it could get infected and needs appropriate medical intervention.


  • Injection site

A lump may form on an injection site but usually resolves within a few days. If it persists, you should call your veterinarian.


  • Abscesses

An abscess is filled with pus and is usually a result of a bacterial infection that develops after a cat has been bitten or scratched. The lump is often red and painful and your cat may try to nip you or shy away when you try to touch it. Placing a warm compress on the abscess may offer some relief. Your vet may prescribe a round of antibiotics coupled with anti-inflammatory medication. Sometimes an abscess is deep and may have a capsule; in which case, there is a need for surgery.


  • Enlarged lymph nodes

Skin lumps may also be enlarged lymph nodes. This can be caused by an ongoing infection or inflammation in the body. A fine needle aspirate (FNA) can help differentiate the potential causes of enlarged lymph nodes. Depending on the results of the FNA, other tests, such as biopsy, may be indicated. The prognosis will depend on the cause of the lymph node enlargement.


Types of lumps on cats

  • Fatty tumors (Lipomas)– may develop anywhere on the body of a cat. Lipomas are benign (that is, not cancerous). Older or overweight cats are more prone to having these growths. Removal of this fatty tumor on cats may not be necessary unless it interferes with your cat’s mobility or function of a specific part of the body.


  • Mast cell tumors — are usually red or itchy and tend to develop on the head or neck of cats. These are some of the more common malignant skin tumors in cats. They have a variable appearance which can make them deceiving. But a fine needle aspirate makes them easy to diagnose. Mast cell tumors need surgical intervention to remove all the cancerous tissue, thus wide excisions may be done. While some types of mast cell tumors can be cured with surgery alone, there are those with a high risk for metastasis or higher chances of recurrence of growth. For these cases, there is a need for chemotherapy or radiation after surgery as part of the treatment regimen. The prognosis for mast cell tumors can vary depending on their nature and extent of growth.


  • Soft tissue sarcoma — The tumor is usually solitary and often develop under the skin rather than on the skin surface. Although they have a lower rate of metastasis compared to mast cell tumors, local recurrence can be a problem especially if wide margins during surgery are not achieved. This means very aggressive surgery is already needed from the start. Surgery is combined with radiation therapy in the treatment of soft tissue carcinomas.

How can you tell if a lump on a cat is cancerous?

After a thorough examination, your vet’s initial diagnosis is often reinforced with other types of diagnostic tests. If you have any concerns about any of the tests, you can always ask your veterinarian so that you will have a good idea of what you and your pet may be dealing with.



The different types of tests that a cat with a skin lump may undergo include microscopic smears, fine needle biopsies/aspirations, incision and/or punch biopsies, and excision biopsies.



Your vet may recommend certain procedures based on several important factors, such as how long the lump has been noticed, including its size and shape. Any recent changes regarding the properties of a tumor should be reported to your veterinarian.


What to do if you find a lump on your cat’s skin

While most lumps and bumps on a cat’s body are benign, there is a need to determine the underlying cause. Having a skin growth evaluated should be your first step after discovering it. The results of the examination and various tests that your vet may deem necessary are used in the formulation of a treatment plan as well as arrive at a prognosis. The treatment plan will depend to a large extent on the cause and could be anything from monitoring to surgery and/or aggressive radiation and chemotherapy of malignant growths. Talking with your veterinarian can give you a clearer picture of the case, including why certain diagnostic tests have to be performed and what is the best treatment strategy that will suit your pet’s needs.



Getting any skin lump examined by a veterinarian as soon as you notice it can give your cat an upper hand in battling the condition, especially if it’s cancer.


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