By Dial A Vet Veterinary Team
Your hand runs over your dog's side during a cuddle and stops on a lump that was not there before. It is a common moment of worry. The reassuring part is that many lumps on dogs are benign, such as fatty lumps and cysts. The harder truth is that neither you nor your vet can tell what a lump is just by touching it. Some cancers feel exactly like harmless fatty lumps. That is why the next steps are simple: record it, get it checked, and get a sample.
Key takeaways
- Most lumps are benign, but appearance and feel cannot reliably tell benign from cancerous.
- Write down where the lump is, its size and what it feels like, and take a photo with a coin or ruler for scale.
- A widely used rule: if a lump is bigger than a pea and has been there for a month, it should be sampled.
- A fine needle aspirate is quick, usually done without sedation, and often gives a diagnosis.
- Some lumps need a same-day vet visit: bleeding, rapidly growing, painful lumps or a dog that is unwell.
Step 1: Take a calm look
Feel the lump gently and note:
- Where it is: for example, left side of chest, two finger widths behind the elbow.
- Size: measure with a ruler or compare to a pea, grape or walnut.
- Feel: soft, firm or hard. Does it move under the skin or seem fixed?
- Surface: is the skin over it normal, red, hairless, ulcerated or dark?
- Behaviour: is your dog licking it or sensitive when touched?
Take a clear photo with a coin or ruler alongside. Mark the spot on a simple body outline, or note it on your phone. This record is very useful for your vet.
Step 2: Check the rest of your dog
Run your hands over your dog from nose to tail. Check:
- The armpits, groin and between the toes
- Along the belly and mammary glands, especially in older or entire females
- Under the jaw and in front of the shoulders, where lymph nodes sit
- Inside the mouth, for any growths on the gums
In Australia, if you live along the east coast, also check whether a lump could be an embedded paralysis tick, particularly around the head and neck. Ticks need prompt removal and a vet check if your dog shows any weakness. See tick paralysis in dogs.
Step 3: Decide how quickly to see a vet
Same day: a bleeding or ulcerated lump, a lump that has grown noticeably in days, a hot, painful swelling, a lump in the mouth, swelling of a leg, or a dog that is lethargic, not eating, vomiting or has trouble breathing. A swelling on the face after an insect sting or snake encounter is an emergency.
Within a week: any new lump that is bigger than a pea, or one that has changed shape, colour or texture.
Within a month: a small, soft lump that has not changed, if your vet has not already looked at it. The Veterinary Society of Surgical Oncology's See Something, Do Something campaign recommends sampling any lump bigger than a pea that has been present for a month.
Step 4: What happens at the vet
Your vet will examine the lump, check lymph nodes and look at your dog's general health. The key test is usually a fine needle aspirate:
- A thin needle is inserted into the lump to collect cells.
- It feels like a vaccination for most dogs, and sedation is rarely needed.
- Cells are examined under a microscope, either in the clinic or by a pathologist.
If the aspirate is unclear, a biopsy may follow, where a small piece of tissue is removed under sedation or anaesthetic. For lumps confirmed as cancer, your vet may suggest X-rays, ultrasound or blood tests to check for spread before surgery.
Step 5: Next steps
Depending on results, your vet may suggest:
- Monitoring: for confirmed benign lumps, such as most fatty lumps. Measure them every month or two.
- Removal: for lumps that are growing, getting in the way, or that are or might be cancerous. Removing a lump early, while small, generally means a smaller surgery.
- Referral: to a veterinary oncologist or surgeon for some tumours.
For an overview of what different lumps can be, see our guide to common lumps on dogs.
What not to do
- Do not squeeze, lance or try to remove a lump at home.
- Do not assume a lump is a fatty lump because it feels soft. Mast cell tumours can feel similar. See mast cell tumours in dogs.
- Do not wait months to see if it changes. Earlier is easier.
- Do not apply creams, oils or home remedies.
FAQ
Are lumps on older dogs always fatty lumps?
Fatty lumps are common in older dogs, but other lumps occur at the same age. A needle sample is the only way to know.
Does a fine needle aspirate spread cancer?
There is no good evidence that a routine aspirate spreads cancer. It provides valuable information for planning.
My dog's lump appeared overnight. Is that worse?
Fast-appearing lumps are often bites, stings, abscesses or allergic reactions, but some tumours swell quickly too. See a vet soon.
How often should I check my dog for lumps?
A monthly once-over at home is a good habit, especially for dogs over seven.
Talk with a vet
If you have just found a lump and want help planning what to do, a Dial A Vet veterinarian can look at photos, talk through what you have noticed and help you decide how quickly to book in. Talk to a Dial A Vet vet. A bleeding or fast-growing lump, or a dog that is unwell, needs an in-person vet today.
References
- Veterinary Society of Surgical Oncology: See Something, Do Something, Why Wait? Aspirate
- Merck Veterinary Manual: Tumors of the skin and soft tissues in dogs
- Vail DM, Thamm DH, Liptak JM. Withrow and MacEwen's Small Animal Clinical Oncology, 6th edition
- Ghisleni G et al. Correlation between fine-needle aspiration cytology and histopathology in the evaluation of cutaneous and subcutaneous masses from dogs and cats. Veterinary Clinical Pathology, 2006
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.