Unfortunately, it’s usually impossible to tell whether a dog’s lump is cancerous simply by looking at it or feeling it. While many lumps are harmless, some can be malignant, so any new lump should be examined by a vet.
Finding a lump on your dog can be worrying, and one of the first questions many owners ask is, “Is it cancer?” The reassuring news is that many lumps in dogs are benign, especially in older pets. However, some skin and subcutaneous lumps can be cancerous, and even experienced vets cannot accurately diagnose every lump by examination alone. Further assessment is often needed to determine the nature of the lump and the most appropriate treatment.
If you’ve only just discovered a lump on your dog, our article What Should I Do If I Find a Lump on My Dog? explains the first steps to take and when you should arrange a veterinary appointment.
Can You Tell If a Lump Is Cancer Just by Looking?
Unfortunately, no.
Some cancerous lumps can appear small and harmless, while some benign lumps can look alarming. Although your vet will assess factors such as the lump’s size, shape, texture and location, these features alone cannot reliably determine whether a lump is benign or malignant.
What Tests Can Be Used?
Your vet may recommend one or more of the following:
- Fine needle aspiration (FNA) to collect cells from the lump
- Biopsy to obtain a tissue sample
- Laboratory analysis by a veterinary pathologist
- Imaging, such as X-rays or ultrasound, if appropriate
- Additional assessment tools, such as Vista iQ, for suitable skin and subcutaneous lumps
The most appropriate test will depend on your dog’s individual circumstances and the type of lump being assessed.
Are Some Lumps More Likely to Be Cancerous?
While any lump should be checked, your vet may be more concerned if a lump:
- Is growing rapidly
- Feels firmly attached to the tissues underneath
- Has an irregular shape
- Is ulcerated or bleeding
- Causes pain or discomfort
- Changes noticeably over a short period
These features do not necessarily mean a lump is cancerous, but they do make prompt veterinary assessment especially important.
How We Assess Lumps at Oathall Vets
Every lump is assessed as part of a full veterinary consultation. After examining your dog, we will discuss the most appropriate next steps, which may include monitoring the lump, performing a fine needle aspiration or biopsy, or using Vista iQ, a non-invasive technology that helps assess many skin and subcutaneous lumps and supports clinical decision-making.
Learn more about our Dog Lump & Bump Assessment with Vista iQ.
Should Every Lump Be Removed?
Not always.
Many benign lumps can simply be monitored if they are not causing any problems. However, lumps that are suspected to be cancerous, are growing, or are affecting your dog’s comfort or movement may need to be removed surgically. Your vet will advise you on the best approach for your dog’s individual situation.
When Should I Contact My Vet?
Book an appointment if:
- You discover a new lump on your dog
- An existing lump changes in size, shape or appearance
- A lump becomes red, ulcerated or starts bleeding
- Your dog is licking, scratching or seems uncomfortable
- You are unsure whether a lump needs investigating
Early assessment gives you the best opportunity to determine whether a lump is harmless or whether further tests or treatment are recommended.
When in Doubt, Contact Us
If you’ve found a lump on your dog, don’t wait to see if it disappears. Most lumps are not emergencies but having them assessed promptly allows us to advise you on the most appropriate next steps and, if necessary, begin treatment as early as possible.
Reviewed by Matthew Clark BVSc MRCVS, Veterinary Surgeon at Oathall Vets
