Help! There's a lump on my pet (part 1)

Lump on a rat. Or is it a rat on a lump? Some lumps can grow so big that even if they aren't malignant, they get in the way. This one was removed, freeing up Lilith the rat here to use her forearm again.

Have you ever found a lump on your pet? This week I’m running a two part series on lumps in companion animals. What are they? What should you do about them? Can you just ignore them and hope they will go away?

It’s very common for an animal to present, either directly for the purposes of examining a lump OR incidentally (e.g. a vaccination, and by the way – is this lump anything to worry about?). 

Part 1 – What is this lump?

I’ve found a lump on my pet. What should I do? Don’t panic. Veterinary patients commonly present with lumps, of which there are many causes. A lump is a collection of cells in the skin (a cutaneous lump), or in tissue beneath the skin. Broadly speaking, lumps can be non-cancerous (for example, an abscess (pus), hematoma (blood) or inflammatory reaction (for example, hives or urticaria), or cancerous (neoplastic). Very occasionally a lump actually contains a foreign body. For example, when I removed a lump from the armpit of a dog, I found it contained part of a kebab stick which had migrated from the gut through the abdominal wall. I have to confess that was a very satisfying lump to remove.

Better out than in: the tip of a kebab stick was found in a lump in the armpit of a dog.

Cancerous lumps may be benign or malignant. There is no way to determine if a lump is cancerous just by looking. Cancer is a tissue diagnosis. That means that a biopsy is required to determine whether cancer is present.

The good news is that many cancers can be cured with early treatment. Contact your vet and arrange an appointment.

Can some lumps go away by themselves? Occasionally, but this is the EXCEPTION rather than the rule. For example, puppies may develop histiocytomas which can disappear. Similarly, warts (or papillomas) may occur (especially in puppies) then disappear over the course of a few months.

Warts in the mouth of a puppy (this puppy is anaesthetised for desexing). They can be tricky to see when the mouth is pigmented like this, but if you look closely you will see rather a lot. Oral warts are not uncommon in puppies and usually occur in multiples.

A close up of a large wart in a dog (the diagnosis was confirmed by histopathology). 

It’s only a small lump. Should I just keep an eye on it? While it can be tempting to “wait and see” if a lump changes or grows bigger, if the lump is cancerous then there is a real risk that the cancer will progress and may spread to other sites in the body during this waiting period. The earlier a diagnosis is made, the better the outcome. The size of a lump alone cannot be used to determine whether or not it is cancerous.

It’s been there for ages. Sure, but that doesn’t mean it isn’t nasty. Cells in a lump can transform into cancerous cells over time. In some cases cancers are slow growing. Being around for months or years doesn’t mean a lump is harmless.

This benign fatty tumour (a lipoma) grew so large that it affected the dog’s movement. Surgery to move very large lumps like this is much more complicated.

Can't you tell me if its cancer just by looking at it? In short, no. Cancer is a tissue diagnosis. You need to examine cells or tissue to make a diagnosis of cancer. Sure, if its full of pus its more likely to be an abscess. Even more so if the patient is a cat who has just been bitten by another cat. But lumps can be misleading. Tumours often develop "necrotic centres" and may appear to be abscesses. 

A malignant mast cell tumour on a dog that has been shaved for surgery. The circle around the lump indicates the extent of margins required to ensure the tumour is removed locally.

What does a biopsy involve? There are different biopsy techniques, ranging from a needle biopsy (where cells are removed from the mass for examination on a slide), to incisional biopsy (a piece of the tumour is removed), to excisional biopsy (the entire tumour and a barrier of normal tissue are removed). The type of technique used depends on the location and size of the lump. Where possible, we take a biopsy prior to performing any other surgery. There are exceptions to this rule: for example, where a lump is found in the testes we usually remove both testes by castration (this is an excisional biopsy).

Sometimes the result will suggest that surgery is not required. For example, in the case of small fatty deposits or cysts, surgery may not be required. Alternatively, in the case of some cancers like lymphoma, medical rather than surgical treatment is used most commonly (with rare exceptions).

Why do you recommend sending biopsies for histopathology? Because cancer is a tissue diagnosis. The most accurate information about whether something is a tumour or not, or what type of tumour it is, is gleaned from histopathology in most cases. The pathologist can look at the cells within the tissue architecture they are invading, and in most cases can identify what is going on – what sort of disease is present, what cells are involved, how aggressive is it (tumours can be graded). From this information decisions can be made about how big surgical margins should be to give the best chance of eliminating the disease. There is a tendency for some clients to see histopathology as an optional extra. In fact it provides valuable information. Removing a lump without doing histopathology is, in some ways, like taking an x-ray and not looking at it. If I perform a biopsy on any of my animals (and yes, I have done so) it goes for histopathology. I want to know what I am treating.

Tune in tomorrow when we talk about treatment of lumps.

Ingrown toenails in pets, and why nail clipping is a good idea

Nails can become a source of pain if not managed. (I met this little dog in the US, and yep someone had painted her nails).

If you’ve not suffered the displeasure of an ingrown toenail before, those who’ve had one can tell you of the seemingly disproportionate pain. Weight bearing, touching or even the vibrations through the ground of someone standing near the affected toe can be excruciating.

We see ingrown toenails in senior pets, most commonly cats but I do see them in dogs and increasingly in guinea pigs. The aetiology is somewhat different to human ingrown toenails but the impact is the same – it causes discomfort, pain, inflammation and often infection. A toenail is, after all, a foreign body which, once it starts growing INTO tissue, the body wants to reject.

One reason I think we see this most commonly in cats is because they are furry. Hairy toes mean it can be hard to see the nail. The second of course is that many cats are “foot shy” – they don’t like their feet being touched, and they’re variably direct about telling you so.

Ingrown toenails are seen most commonly in older cats, I suspect because arthritis means it can be hard to bend and flex to reach and groom the toes – and it may be harder to use enough strength when employing a scratching post or similar to remove the offending nail.

The sum total of this is a nail which keeps growing.

So I thought I’d show what such a nail can look like and demonstrate how big they can be.

This cat had two other ingrown toenails. Note this one extends from the nail bed (top) curling right around and inserting into the tissue of the toe.

What to do to avoid these? Regular nail trims. Though I’ve done thousands of them, in most cases I need someone (ie a vet nurse) to hold the patient while I trim the nails (especially guinea pigs). Just about every vet clinic provides a nail-trimming service.

Better out than in. A huge ingrown toenail is removed. Note how sharp and pointy that thing is at the end. Not nice at all.

It’s well worth getting young pets used to you handling their feet, and trimming nails regularly. They grow back pretty fast. For pets with arthritis, sometimes pain relief solves the problem of overgrown nails if it allows them to weight bear to an extent that the nails can be worn down naturally, or if it enables them to groom properly.

Guinea pig in position for a nail clip. This nail clip was being performed by the owner of a guinea pig at a guinea pig show.

This is another pic from the US (hedgehogs are exotic to Australia). This little hedge is having a nail clip.

From a veterinary perspective, these are one of those problems that feel really good to solve. There’s the nail, then it’s gone – and the animal can walk properly again (though multiple ingrown toenails in the same animal at the same time are more common than not so it’s usually a repeat process til they are all gone). I never get bored of removing them (I never get bored of hedgehogs either).

Guinea pig treat: fennel

Fennel. You just need to paint some eyes and eyebrows on the bulbs and they look like Beaker from the Muppets.

A few weeks ago I wrote this post on making your guinea pig/s a salad and what to feed guinea pigs in general. Jennifer from Oxbow suggested I try fennel tops.

Fennel tops! 

I'm a simple girl, I only learned about fennel when it was on Masterchef and whilst I have sampled fennel cheesecake, a good old fennel bulb is something I consider more appropriate in a still-life (don't they look like a heart?) than the kitchen.

I asked where she gets them and she replied: 

They generally sell just the fennel bulbs for human salads at the shops so I bought a plant at Bunnings years ago. It went to seed even with daily picking and its seedlings are now available almost year round here in SE Queensland climate.  Oxbow’s original Critical Care is aniseed flavour because that is very popular with pigs.  Then I read somewhere that fennel is an aniseed (liquorice) flavour and thought I’d give it a go.  Well, the little ones here have definitely approved.  You’ll have to let me know if your little neophobes agree!

Well, Jennifer, lets see.

Exhibit A: A small arrangement of fennel leaves prepared for the boars.

Turns out I have been depriving them! They took to the fennel leaves like ducks to water.

Radike Samo and Randy, who run in the other direction most of the time I present a new vegetable, go berserk over fennel.

Thanks for the excellent tip Jennifer. Its not something I would feed them every day, but if I do find myself with a fennel plant or whipping up a fennel cheesecake I will know what to do with those leaves. I also discovered that the bulbs make excellent objects to hide behind, although I didn't want to leave them with the boars in case they went on a fennel binge.

Busted: the extra rinse cycle

Ever wondered how the dishes you began to stack got cleaner when you left the room to catch something important on the news? Ever wondered how your dog's bottom expanded slightly even when you put him on a diet? Wonder no more. (Although some mysteries in life are better unsolved).

What is anthrozoology? AND: Pet health and toxins

Anthrozoologist Associate Professor Pauleen Bennett

Last month I had the pleasure of interviewing the inspiring Associate Professor Pauleen Bennett - President of the International Society for Anthrozoology and Chair of the Australian Anthrozoology Research Foundation.

Anthrozoology is the study of human-animal interaction, and Pauleen is an inspiring scientist and animal lover. I don't want to give away too much, but she is one of the few people I interviewed who has an explicit plan to save the world - and pets are involved.

For those of you who live in Victoria, Pauleen is giving a series of lectures. I feel like I always come away from her lectures with a plan of action. If you're interested, book here.

In other news, Sydney Morning Herald journalist Lissa Christopher interviewed me for a story about toxins that affect the health of dogs. You can read it here - and even if you don't feel like reading a lot, its worth a visit just to see Nick Glavin's GORGEOUS photo of Rosie the boxer.