Is Your Dog’s Lump Cancer or Not? (how to tell)

If you’ve found a lump on your dog, how can you tell if it’s cancer or not? It’s always best to know when a mass is still small, rather than leave it to get very big before getting it checked out. Larger lumps are harder (and more expensive) to remove than small ones after all.

Thankfully, there is a simple technique that will let your vet know what a lump is that is quick, cheap and painless!

is a dog’s lump cancer or not - how to tell

Tucker has a wart-like cyst on the outer flap of his ear - about 3 mm across and round. It’s clean and does not appear to be infected. How do I remove it? - Stuart 

First things first, only a qualified veterinarian can perform an act of surgery on an animal. That is a legal requirement. I certainly would not encourage you to go chopping bits off your dog willy-nilly!

Different Types of Mass

Whether this mass needs removing or not is the next question. Different types of masses, they do need to be approached differently. 

Benign Tumors

We have things like skin tags or sebaceous cysts, which are benign lumps. Benign means that although they are growing in that local area, they will not spread to other parts of the body and cause problems elsewhere.

We have benign masses like skin tags or sebaceous cysts. Also, lipomas would fit into this category, which are a very common lump that we get, generally under the skin of larger breed and especially overweight dogs.

These can often be safely left if they are not causing a problem, ulcerating or growing rapidly. That’s not the case for all benign tumors however. Another reason to make sure any mass is checked, even if it appears pretty innocuous.

Malignant Tumors

Malignant tumors are nastier types of mass. They can be really invasive locally. They can cause real problems with where they are or because they often ulcerate. The other big issue with malignant tumors, cancers, is that they spread to other parts of the body. Typically, that's the lungs, but it can also be the liver and kidneys or anywhere else really. Secondary tumors can form elsewhere in the body.

These tumors ideally need to be removed and some of them will need to be removed with a really wide margin. Your vet will have to go quite a long way outside of where the obvious tumor appears to be to try and make sure that we completely remove that mass.

Diagnosing Mass Type

So how do we know if a tumor is a benign lump and we do not need to worry about it, or if it is a malignant lump That really needs to be either removed or treated aggressively som other way?

Well, ideally all masses or lumps that are larger than a pea or that have been present for longer than a month should be checked out by your vet.

ideally all masses larger than a pea or lumps that have been present for longer than a month should be checked out by your veterinarian

Fine Needle Aspirate

The quickest way that we can check mass type is to perform something called a fine needle aspirate or an FNA.

What happens here is we take a small, thin needle and we pop that into the mass. We then suck up a few cells using a syringe or by moving the needle backwards and forwards into the mass. After the sample is spread onto a slide and stained, your vet can look at the cell type under the microscope. In some cases the mass will be sent to a pathologist for their opinion of mass type.

That is a well-tolerated test. In the vast cases, we do not need to administer any sedation. We do not need to worry about local anesthetic or anything like that. A dog and a cat won't really notice that the test is being carried out.

Now, in some cases, for example, if a mass was really close to an eye or a dog or cat was really sensitive because the lump is really sore, then it might be that it is not the best option and we need to sedate them. After which, we can carry out a fine needle aspirate or an FNA or it might be that we want to take a further, larger biopsy.

Another consideration is that a fine needle aspirate does not always give an absolute, definitive diagnosis. Meaning that we don't always get a specific answer. The reason for that is you can appreciate, we are just taking a small number of cells, so it might be that we're actually missing the main problem area within that lump. It might be that we get a few dead cells for example, within the middle of a tumor.

We do not always get a very good answer, but that's a really simple first step.

The next step, if a diagnosis is not reached, or your pet is being sedated, would be to perform a biopsy. This is when a much larger piece of tissue is removed, and in most cases tends to give a specific answer as to the type of mass you pet has. For smaller lumps, an excisional biopsy is often performed. This is when the entire mass is removed before knowing exactly what it is. The answer only being known after being submitted for histology.

Surgery or Not?

Once we've got that proper diagnosis of the problem, we can move on to planning surgery. It might be that surgery is not needed. It might be that actually, yes, we do need to do surgery but we need to look a little bit closer at the potential the cancer has already spread. 

We might need to take some samples of the lymph nodes, or it might be that we want to plan a more radical surgery just to make sure that we have the best chance of removing all of the tumor margins without leaving any cancer cells behind.

Some tumor types will also benefit from additional treatment techniques, such as chemotherapy or radiotherapy. Getting a specific diagnosis and staging the cancer is very important in a lot of cases.

Now, in Stuart’s case with his Vizsla, a wart-like cyst on the outer flap of his ear, I suspect that it is a benign lump, but there is no way that anyone can say that without actually looking at it in-person. 

It might be that your vet takes one look at it and goes, “No, that is just a skin tag. We don't need to worry about it. Let's just leave it alone”. If it is not causing any problems, not growing and not a nasty tumor then why actually remove it in the first place? You can just leave it alone as the mass is essentially just a cosmetic problem.

The above is a transcript taken from “The Dr Alex Answers Show”.

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