My dog has a lump – should I be worried?

Many dog owners are understandably concerned when they find a new lump on their pet. Vets regularly see lumps that are associated with infection and inflammatory reactions, as well as tumours. It is important to get your pet checked out if you find something that is worrying you, so that the cause can be determined, and the best care can be given.

In this blog, we will look at some of the most common types of lumps, as well as the steps our vets might take to investigate and treat them.

What are the most common lumps?

Most of the lumps that owners find at home will be external, on their dog’s skin or the underlying soft tissue. There are many different causes for lumps and bumps in dogs including (but not limited to!) the following:

Infection

Abscesses may come up like a lump and can be caused by bite injuries, tooth root infections or foreign bodies. Abscesses can be inflamed and sore, usually containing pus. They may come up quickly compared to other slow-growing masses.

Haematomas

A bleed under the skin may lead to swelling. The most common haematomas seen in veterinary practice are aural haematomas. These occur in the pinna (ear flap). They are usually secondary to an underlying ear infection, which has caused the dog to head shake or scratch at their ears. The ear flap may suddenly appear swollen and heavy.

Cysts

A variety of cysts can occur on our pets. Sebaceous cysts are benign build-ups of thick sebaceous material. These can reach a point where they burst, or they may stay as a firm lump underneath the skin. Interdigital cysts are common in the paws of dogs with skin allergies and look like a grass seed foreign body. A firm red swelling appears between the toes causing discomfort. Other cysts may be non-painful and filled with watery fluid.

Parasites

Ticks can often be mistaken for small lumps by owners. These parasites attach to your pet while small and gradually fill up with blood as they feed. They may reach the size of a small jellybean. Also, some animals can react to flea bites leaving them with small scabs or raised areas on their skin.

Benign tumours

Benign tumours are abnormal lumps that grow locally and don’t spread around your pet’s body. One of the most common benign tumours found in dogs is lipomas. Lipomas are tumours of fat tissue and often feel soft, mobile, and rounded. They can vary in size, with some being slow growing whereas others can grow quite rapidly.  They are most common in middle-aged to older animals.

Conversely, histiocytomas are much more common in younger animals. These lumps present as a small, inflamed mass in the skin, which will regress (disappear) again by itself over time. However, it can look very similar to other more sinister skin lumps, so testing is usually advised to get a definitive diagnosis.

Skin tags are commonly seen in older dogs. They are also known as acrochordons, and they are made of collagen fibres and blood vessels. Treatment is usually only indicated if they become inflamed or cause discomfort. Another common finding in older dogs is warty-looking growths often found in Poodles, Maltese terriers, and Bichon Frise. These are often sebaceous adenomas (tumours of sebaceous glands) that rarely cause issues unless they become sore or irritated.

Malignant tumours

A range of malignant or cancerous tumours exist in cats and dogs. One of the most common types we see in dogs is mast cell tumours (MCTs). The appearance of these varies considerably, and they can also increase and decrease in size. They can vary from low-grade (not very aggressive) to high-grade (highly aggressive). MCTs can release histamine, a natural body chemical that causes inflammation, like when we get an insect bite or sting. This is why they can become swollen, itchy, and irritated, as well as causing problems elsewhere in the body.

Malignant melanoma is another relatively common tumour in dogs. It develops from pigment-producing cells (melanocytes), which gives these tumours a dark colour in many cases. They can be commonly found in the nail beds, causing an abnormal-looking claw or swollen toe, and the gums or lips, but can be found elsewhere on the body too. Unlike in people, it is not typically caused by sunlight exposure. As with MCTs, melanomas can spread elsewhere in the body, such as the lymph nodes and chest.

Lymphoma can affect both cats and dogs and may cause enlargement of your pet’s lymph nodes. Enlarged lymph nodes may be felt as firm rounded lumps in your pet’s neck, near their shoulder blades and the back of their hind legs. Diagnostics will need to be performed to confirm cancer, as lymph nodes can be enlarged for other reasons such as inflammation or infection.

Mammary tumours are very common in dogs, and these can vary in type. Not all tumours are malignant, roughly 50% turn out to be benign, and further investigation will be required to work out which type your pet has.  However, it’s always worth investigating because malignant mammary carcinomas can spread elsewhere in the body, such as the lymph nodes, other mammary glands and organs.

Soft tissue sarcomas (fibrosarcomas) are tumours of connective tissue. They can be locally invasive and are more frequently found in large breed dogs, but can be found in cats too. They can metastasise and spread around the body, but this is less common than some other tumour types. However, their locally invasive and fast-growing nature can cause issues, and they often need wide surgical margins to remove.

Osteosarcomas are tumours of the bone. They can cause firm lumps or bumps to form in the bone and are commonly found in animals’ limbs; sometimes, the first sign is a broken limb as the weakened bone fractures. They will also cause pain, and lameness and sadly the tumour has often metastasised elsewhere in the body by the time of diagnosis.

How will my vet diagnose the problem?

Your vet will start by discussing the problem with you. It can be helpful to tell them when you first spotted the lump and how quickly it is growing. It is also important to remember where the lump is so that you can show the vet during the consultation. Some owners may trim a little fur in that area if it can be hard to find.

Your vet will then examine your dog. They will assess the size of the lump and whether it is firm, soft or fluid filled. A full physical examination allows them to check for any other abnormalities as well as the lump itself. Your vet may be able to give you some information about the lump during the consultation or they may suggest further investigation. This might include:

Fine needle aspiration

This involves Inserting a small needle into the lump to draw out some cells for analysis. The sample may be looked at by your vet or sent to an external laboratory. Cytology (examination of cells) can give us more information about the mass and what next steps may be required. Sometimes the results may be inconclusive, and further tests may be required. Fine needle aspirates from lymph nodes could be advised as well if your dog has been diagnosed with a malignant tumour. This can help to assess whether it may have spread.

Biopsy

A sample of tissue from the mass may give further information. An excisional biopsy means removing the lump altogether and sending it for histology (examination of tissue). Sometimes an incisional biopsy is needed. A few smaller pieces of tissue are taken from the lump, to find out more about it before a more radical surgery or removal of the lump is planned.

Diagnostic imaging

Diagnostic imaging such as X-rays, ultrasound scans or CT scans, may be advised to find out more about whether a tumour has spread elsewhere in the body. Metastatic spread to the lungs, liver and spleen could occur. This helps your vet determine the stage of the tumour and gives you a clearer understanding of your pet’s prognosis.

What treatment options will be available?

The treatment will very much depend on what your dog’s lump is. An abscess may be treated through lancing, flushing and antibiotics. A benign lump like a lipoma or sebaceous adenoma may just be monitored.

However, some lumps need surgical removal. This may be straightforward if the mass is small and there is plenty of skin to close the wound afterwards. It can be more complicated if the mass is very large or invasive. Amputation could even be recommended for some bone tumours or soft tissue sarcomas.

Chemotherapy may be suggested following any recommended surgery to ensure that any microscopic cells from the tumour ‘are mopped up’. This can extend your dog’s potential lifespan. This could involve regular oral medication and possibly medication via a drip too.

Radiation therapy uses high-energy radiation to shrink or kill cancer cells. It may be used when surgery isn’t an option due to the location of the lump, or following surgery to mop up any remaining cancer cells.

Other treatment options may also be available depending on the type of lump your pet has. Your vet will be able to talk you through all the options, based on their diagnostic findings. Please discuss any questions or concerns you may have with them; our vets are here to help.

Summary

The good news is that most lumps we see in practice are benign and easy to manage. But it is important to get your dog checked, in case they are one of the unlucky ones. The sooner we make a diagnosis the sooner we can discuss treatment. This may mean they have a better long-term outcome.

Our vets can only give you the best possible advice if we examine your pet, so please call us today on 0151 428 8600 or contact us via PetsApp. Hopefully, we can help to put your mind at rest or offer a plan if things need to be taken further.

FAQs

Why does my dog suddenly have a lump?

Some lumps can appear suddenly if they are due to infection (abscess), inflammation or a haematoma (blood swelling). However, it may just be that a small lump has been unnoticed until it has reached a certain size, or perhaps it has started growing more rapidly lately. It is best to get any lump checked out by the vet for a diagnosis.

How do I tell if my dog has a cyst or a tumour?

Cysts are fluid-filled structures so may feel soft or have material that can be expressed from them. However, it can be really tricky to tell the difference between cysts and tumours sometimes. A fine needle aspirate performed by the vet may help work out what type of lump your dog has.

Are cancer lumps on dogs hard or soft?

Many cancerous lumps can be firm to the touch, but there can be some softer ones too. It is hard to make a definitive diagnosis just by feel, so your vet may talk you through further test options.