Your sitting there patting your dog in the same position as always, and then one day you notice a lump under his skin. Naturally, your mind starts scrolling through the worst possible scenarios, coupled with an increased heart rate and a feeling of anxiousness. Lumps always catch us by surprise.

The most common lumps found under the skin are fatty tumours (Lipomas) which are benign, meaning they are not cancerous. Lipomas are commonly found in older dogs, but any age, breed or gender can develop a lipoma. While any lump is scary, it is important to remember that lipomas are nothing more than an ugly fatty lump that often does not require surgical removal. It is only when the lipoma is affecting a dogs comfort and ability to move that it requires surgical removal.

These fatty lumps tend to grow under the skin on the neck, upper legs, underarms and torso. They can grow anywhere on the body, including muscle tissue. If it is a lipoma growing under the skin, you will be able to move it around a little and it will have a squishy texture. If it has grown in the muscle then it will feel quite firm.







While lipomas are the most common lump that potentially requires intervention, there are a number of others to be aware of and keep an eye out for. If you notice any lumps suddenly appear, or any previous lumps change in size, colour or feel, then I highly recommend that you seek the advice of your veterinarian. When it comes to lumps… never self diagnose. The key is finding it early so you have the opportunity to seek prompt treatment if required.






As previously discussed, this is a fatty benign lump/tumour that grows just beneath the skin's surface. It commonly grows on the neck, upper arms, underarms and torso, but it can grow anywhere, including in the muscle. This is a benign lump, meaning non-cancerous. Senior, overweight and large dogs tend to be more prone to these lumps.




Via a fine needle aspirate (FNA), where the veterinarian will use a needle and syringe to ‘suck’ out some of the cells from inside the lump itself. These cells are then placed on a slide and dyed so they can be viewed under a microscope. The veterinarian can then diagnose if the cells are benign and fatty or if further testing is required (sent to the lab for a pathologist to examine).




For the most part, these lumps are just left alone. If they are creating issues, such as a lump in the armpit impeding a dogs ability to walk, or a large lump on the chest that continues to get scratched and bleed, then surgical removal under a full general anaesthetic would be recommended.




This is a blocked oil ducts in the skin that rarely is anything to worry about. Sebaceous cysts look like a pimple and expel a white, pasty substance when squeezed.




While these are benign lumps, they can be difficult to distinguish from other lumps. For this reason, an FNA is conducted to complete the diagnosis. If your veterinarian can not confirm the diagnosis at this stage, they may recommend a biopsy to be sent to a laboratory for testing.




These swellings sometimes become red and sore and are usually found in older dogs in the middle of their back. Generally, these do not cause problems and are left alone unless they become infected or irritate your dog.





These are a buildup of pus underneath the skin, caused by an infection from a bite, sting,  puncture or bacteria from an animal, object or internal growth (e.g. infected tooth causing a tooth root abscess). With prompt treatment, there is generally no need for concern.




Abscesses appear as sudden points of pain that can be firm to touch or soft and jelly-like. These are diagnosed with the appearance of:

  • Inflammation, pain and redness
  • Heat
  • Loss of appetite
  • Fever
  • Lethargy
  • Licking or chewing at the lump
  • Bleeding or oozing around the lump
  • Putrid smell


If the lump does not have any discharge, your veterinarian may insert a needle to suck out some of the contents to confirm that it is puss in order to determine an official diagnosis.




Treatment includes lancing of the abscess to drain it properly, along with antibiotics to help fight and prevent further infection. Anti-inflammatory drugs may also be prescribed to reduce swelling. In extreme cases, surgery may be required to remove the abscess, but most commonly the former treatment is more than sufficient.



These nasty tumours are the ones that we want to avoid and are a tumour of the immune system blood cells, and comprise of up to 25% of all tumours. Mast Cell Tumours are most commonly seen in Boxers, Boston Terriers,  Labradores, Beagles and Schnauzers and dogs over 8 years of age. This cancerous tumour can be confused with other lumps making it imperative to have each new lump checked by a veterinarian.




Initially your veterinarian will take an FNA from the lump to examine the cells under a microscope. If the cells are suspicious of a MCT then they will likely conduct a biopsy that will be conducted under a local or full general anaesthetic, depending on your dog.

After diagnosis, an ultrasound, radiographs and CT scan may be conducted to confirm the extent of the spread.




Diagnosis of a MCT is scary, but the good side is that there are options. Surgical removal is step one, if possible, and the entire tumour can be removed. From there, chemotherapy and palliative therapy are options depending on the extent of the MCT spread.



Mammary carcinomas are breast cancer, or, cancerous growth of the mammary tissue,  and are more common in non-dessexed females. Lumps in the mammary glands can be benign but it is always best to have them checked. Mammary tumours in male dogs these are often malignant.




Diagnosis of a mammary carcinoma is effectively the same as a mast cell tumour. First, an FNA is conducted, along with a biopsy if necessary to confirm diagnosis. Then scans and/or radiographs to confirm the spread, if any. The treatment plan will be devised by your veterinarian after all of the information has been collected.




Surgical removal of the tumour is required to give your dog the best chance. Some veterinarians prefer to remove the uterus at the same time if it is still intact. There is currently no evidence confirming that by conducting a ovariohysterectomy at the same time reduces the chances, or prevents the reoccurance of another mammary carcinoma in the future.



These are not caused by sunlight and are much less malignant in dogs then they are in humans. In dogs, melanomas are tumours involving cells that give pigment to the skin. In appearance, they are dark lumps that are slow growing, and can be either benign or malignant. They tend to be more aggressive when growing on the mouth and legs and are generally removed, but often still re-occur.  




This is confirmed by a biopsy of the tumour itself and testing by a laboratory. The examining pathologist will grade the specimen according to how actively the cells are replicating. This gives an indication on how likely this tumour is to spread.



Surgical removal is step one. If the entire melanoma can not successfully be removed, chemotherapy may be recommended to continue treatment and aim to reduce and/or prevent further spread.





These are locally invasive tumours of the skin's connective tissue that grow fast. More commonly found in large breeds, a biopsy is required as they can often be mistaken for a lipoma as they feel much the same when palpated.




For an accurate diagnosis, an FNA must be conducted, along with a biopsy under a local or full general anaesthetic. A pathologist can provide a detailed and accurate diagnosis, allowing the veterinarian to develop a specific treatment plan.  



Surgical removal is the best form of treatment, from excision of the lump to removal of the limb in extreme cases. With fibrocarcinoma, it is important to note that complete removal of the tumour is often not possible due to its location as well as its aggressive nature. It is difficult to remove a tumour that is surrounding tissue and leave enough skin to successfully close the incision.





Appearing as raised red lumps that contain a surface crust, these lumps are found under the skin and hold a firm consistency. They look similar to a highly aggressive tumour so vets often recommend a biopsy, surgical removal or an FNA. Surgical removal is most commonly required.




As with every lump, an FNA and potentially a biopsy is required to confirm diagnosis.




Surgical removal of this lump is most commonly the recommended treatment.










Haemangiomas are tumours of blood vessels or underlying tissues of the skin. Constant exposure to the sun can lead to their development and growth, however this is not always the case. Commonly seen on the abdomen of dogs that take a particular interest in sunbaking. Surgical removal, along with pathology testing is often a sought after choice as these can change over time to become malignant.




Biopsy is required for a final confirmation of these lumps.




These are often benign and more of an eyesore than a problem. They can change from benign to malignant making surgical removal a common treatment for these lumps.





Dogs that have lived an unhealthy lifestyle for most of their life are known to be more prone to developing lumps, particularly lipomas.

There are a number of things that could increase the chances of your dog developing lumps:

Age - Older dogs by nature are more prone to developing lumps

Poor diet - Feeding a processed diet, your pet is getting a dose of chemical additives and carcinogenic byproducts like heterocyclic amines and acrylamides with every bite. Over vaccination - Overdosing with vaccines allows for a build up in the system of unnecessary chemicals and toxins

Long term obesity - Obesity keeps the body at a constant state of inflammation, inhibiting it from proper growth

Toxic chemicals and substances - Households containing smokers, the use of strong cleaning chemicals and air pollutants create a build up of toxins in your dog's system over time



The best chance to avoid fatty tumours from forming is to keep your dog in good physical condition. The goal is to support his metabolism, immune and lymphatic system, and organs for proper detoxification. Think of it like your children’s health, or your own… maintaining a healthy lifestyle and limiting the exposure to chemicals is common sense for us to maintain a healthy life into adulthood and our senior years. Our dogs are not different.

Here is a great short video by Vet Know-How on common lumps, diagnosis and treatment. It also demonstrates an FNA (fine needle aspirate) so you can understand how one is performed. 







Simple… keep your dog safe from everything above! Just kidding… it is difficult to control every one of the points listed above, but the key us to meet most of them as best you can. If you can do all, awesome… you are the perfect dog mum! But if not, do not hate yourself for it. Work on the points that you can and know that you are doing your best.



If your dog does develop a lump, hope that it is benign and be grateful that there are treatment options for each.



If you have any experiences that you would like to share, or have any questions, please reach out to me. I would love to hear from you.



Belinda Bird

Founder & Veterinary Nurse



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