What is a lump?

A lump is a swelling or growth that can appear on or under your pet’s skin. Finding a lump on your pet can be a worrying time but try not to panic – not all lumps are nasty. Lumps and bumps are more common in older pets but they can be found in younger animals too. Swellings or growths can simply be caused by a bruise or even an abscess so is not always a cause of concern. Whilst some dogs can develop cancerous growths please remember that there are many treatment options available. If caught early most cancers are treatable; just keep an eye on your pet for any new lumps and get them checked by your vet as soon as you notice them. 

Is it cancerous?

A lump can be either benign (non-cancerous) or malignant (cancerous) but it is not usually possible to tell the difference simply by looking at it. Some form of testing will be required to determine if the lump is cancerous. There are many testing options available that your vet can advise you about. 

Benign lumps are simply an overgrowth of cells. They tend to grow slowly and don’t spread to other parts of the body. However, benign lumps can be irritating to your pet and may become troublesome if they grow to a large size, as this may make it difficult for your pet to move around. Malignant lumps are cancerous, they tend to grow more quickly than benign growths and can spread to other body parts. 

Your vet will be able to test the lump to help determine the type of growth your pet has and what treatment is required. 

What testing can be done for my pet? 

The testing recommended by your vet will depend on the type and location of the lump.

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Most lumps can be sampled easily and with only minor discomfort by placing a needle into them and gathering the cells contained within. This test is called a fine needle aspirate (FNA). The sample of cells is placed onto a glass slide and this is then sent to the laboratory – either in your practice or an external lab. The results are usually available within a few days. The type of cells present can help the pathologist identify the nature of the growth but not always. Occasionally a diagnosis can only be achieved by taking a tissue biopsy. 

If your vet suggests a tissue biopsy is necessary, your pet will need to be sedated (and given local anaesthetic) or given a general anaesthetic to take a sample of tissue from the lump. The sample is then sent to the laboratory for analysis. The results will be ready in a week or two and when available the vet will call you to discuss them. 

If your vet is worried about a cancerous lump, they may suggest additional tests such as x-rays to check if the tumour has spread to other body parts.

What is done to prepare for surgery? 

Lumps that are bothering your pet, growing and interfering with your pet’s movement or those that are malignant are best removed surgically as soon as possible. Surgical removal of a lump needs to be performed with your pet under a general anaesthetic, which puts your pet into a state of unconsciousness. 

Under general anaesthetic, your pet is effectively asleep and cannot feel pain. Once asleep, a tube is placed into their windpipe so that their breathing can be controlled and monitored. Your pet will be placed onto a table and the area of hair around their lump will be shaved. You may wonder why such a large area of hair needs to be removed; this is to ensure the area is clean and sterile. Inadequate clipping may result in hair becoming trapped in the wound. Causing the development of an infection which will also delay the healing process. The skin is then scrubbed clean with surgical soap. A sterile drape with a window is placed over the affected area, ready for the surgeon to make an incision. 

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What happens during surgery?

The surgeon will typically make an oval incision around the lump to ensure that the skin edges come together nicely when stitched. The size of the wound your pet has depends on the size and nature of the lump. It may be larger than you imagined. Smaller lumps generally have smaller wounds whilst malignant lumps require larger incisions to ensure complete removal of the tumour. 

Occasionally, large margins may result in the surgeon being unable to close the wound with the remaining skin. If this happens, it might be necessary to perform skin grafts or flaps. This involves using skin from another area of the body. At the end of the procedure, the incision will be closed with stitches, in two or three layers. The inner (muscle) layer first, then the middle (fat) layer and finally the outer (skin layer). The number of layers will depend on how deep the tumour is located and the type of tumour. 

Once the lump is removed your vet may recommend that it is sent to the lab for further analysis. This is to confirm the diagnosis and to also assess the edges of the sample to ensure the lump has been removed entirely. Your pet will have been given pain relief during the procedure. Once completed they will recover under the close supervision of the veterinary team. 

What happens after surgery?

Depending on the type of surgery and your pet’s recovery, it may be necessary to keep your pet in the hospital for a night or two.

When it is time for your pet to go home, your vet will provide you with specific instructions. Your pet will be given pain killers and any additional medication deemed necessary by your vet. It is important to follow all the instructions closely to reduce the risk of complications. 

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You should monitor the wound daily for any bleeding, swelling or discharge and contact your vet should this happen. It is important to prevent your pet from licking its wound. Use an anti-licking device such as an Elizabethan collar (the dreaded ‘cone of shame’). Ensure your pet is well-rested to give it the best chance of a speedy recovery.

Your vet will schedule a post-operative check one to two days after discharge to see how your pet is doing. Your vet will schedule another appointment approximately 10-14 days after the surgery to remove any stitches (if necessary). 

If you are unsure about anything or concerned about the recovery of your pet at home. You should contact your vet as soon as possible.