Firstly, if you have found a lump, try not to panic. It can be worrying when you discover a lump or sign of illness on a much-treasured pet; but we will discuss lumps in rats and why it’s not always as bad as it might first appear. However, we would always advise you to seek your vet’s advice if you notice a new lump suddenly appears.
Rats are prone to various types of lumps, which can be growths or swellings, They may appear suddenly or slowly grow over time and can be located anywhere in the skin. It is important to check your pet regularly for any lumps. It may also be useful to note down any other changes in the rat’s behaviour or day to day routine that may coincide with the lump appearing.This might include a change of appetite, demeanour or any signs of sickness, as your vet may ask you about these.
Types of lumps
Some of the main lumps that rats can develop are swellings from injuries or infection (abscess), they can get fatty growths (lipoma) and also mammary lumps. These can be categorized as either a non-harmful growth (benign) or a nasty growth that can spread in the body (malignant). If they are non-harmful, they can still grow to be very large and depending on the location may cause problems walking or eating for example. The more harmful types of lumps may spread to other areas of skin or spread internally, causing other symptoms or problems.
Infection & Swellings
These can be caused by fighting between groups of rats or an injury from an object in the environment and can vary in size. They will often feel soft and can be painful, so we advise you to be gentle when handling your rat. In addition, it may be worth checking the housing for any sharp or damaged areas that could have caused an injury. An infection often needs treatment to help it resolve fully so we would advise seeking your vet’s advice.
Fatty tissue (Lipoma)
These are generally soft and often move around when felt and they do not tend to bother them. They are not painful but may cause discomfort if they press on a leg when walking. It can be hard to tell if a lump is made of fatty tissue or not by simply looking at it.
Mammary (breast tissue) lump
These are the most common type of lump seen in rats and can appear in both males and females. They can appear in young rats also and are often mistaken for other lumps as they can actually be found over a wide area of the body from the neck down the length of the body underneath, due to the large amount of mammary tissue. They are not painful and are mostly a non-harmful type (fibroadenoma) but can grow very large, with a very small percentage of them being a nasty type. It is not uncommon for rats to get multiple lumps of this type over time.
Can I leave it alone?
To answer this question, we need to determine what type of lump is present and for this an examination and sometimes a biopsy is needed, which usually involves an anaesthetic. Once it is determined what type of lump it is then more information can be given as to whether surgery or another treatment is required.
So, to answer the question of will the lump go away, we would advise you seek your vet’s advice on the next step, if a small swelling due to trauma is diagnosed this may well go on its own.
Discussion
Hi I have a four year old female rat who had an opening by her vagina and then it close with me cleaning it. It now it is open again and now there is what looks to be white puss and a big whole by her anus. I’m not sure what this is but I don’t think there is much to do except euthanasia, as she is very old. Is there anything else I can try to heal it? Or is this time for her to be at peace?
At 4 years old, a fistula like this is very unlikely to heal properly – at best, it will close on the surface leaving an abscess underneath, which it sounds like is what happened.
I’m really sorry to say that I think the time has come to say goodbye and let her rest.
Odis, our wonderful rat of 2 and a half years, passed away yesterday. He developed a small lump on his side which eventually grew so big, that it was double the size of him. He didn’t seem to be in pain and still ate something until his last breath. No vet in our area would assist us. They said they only do dogs and cats 🙁 My daughter held him when he took his last breath and we cried so much. RIP sweet Odie
My Rat is a little over 4 years old and she has a lump in front of her back left leg and we don’t have a vet in our area it’s not a very big lump but it’s there and she’s still walking and jumping around like normal, what should I do?
There’s nothing really you can do without veterinary examination. The probability at that age is that it’s a tumour, but it may well be benign. There is the possibility it’s an abscess, but if it’s not bothering her, a tumour is more likely. It may well grow to be a problem, and mean she needs to be humanely euthanased in the end, so I would suggest a vet check if you want to know what it is – but at this age, the odds are that surgery wouldn’t be in her best interests anyway.
My little boy just hit the year mark. He has started breathing abnormally. Very quick, shuddering breaths. He has started sneezing and snotting, too. I picked him up for the usual check and found a mass growing on his chest. He is underweight now, as well. The mass feels oval in shape and is a bit soft. Maybe sponge like and rolls around to the touch. He is unbothered when I inspect it. But it just seems like he is getting more lethargic as time goes by. I don’t know what to do.
OK, I’d very, very strongly advise a vet check ASAP. Many of these lumps are benign and can be treated, if addressed early; in addition, his respiratory problems may or may not be caused by the mass. But you REALLY need to get him seen by a vet!
I appreciate you reaching out. I took him to a vet but she was not very helpful. So, looking up his symptoms showed he may have had pneumonia…possibly. Either way, he has passed. He died in my lap, gasping for breath. I have two more boys who have lumps forming, though. But they show no signs of distress at all. They will be going to a vet soon.
I’m really sorry to hear that – but yes, that does sound a wise precaution with the other boys.
I just noticed my older female rat has a lump under her front arm, and there’s a little bit of blood on her nose. Her younger sister in the cage has no marks or blood on her, and seems healthy. My older one loses balance on her back left leg whenever she’s walking, and is breathing kind of hard. She’s a rescue from a very neglectful household and I’m not sure what my next step would be considering my city doesn’t offer the best rodent vets.
I really do think that trying to find a vet with some rodent experience is important here – this is quite likely to be a tumour, but if addressed early, the prognosis is much better than most people think. I really don’t like the heavy breathing or blood on the nose, though, as this sugegsts there’s something seriously amiss. Good luck finding someone – where are you based? There may be someone who can recommend a vet with rodent expertise?
I just spotted that one of my female rats has a bump on the side of her stomach. It doesn’t seem to bother her, she is still active and can still climb like normal. I left it for the night and the next day I checked on her and the lump got bigger. I did some research and I think it either is a Fatty tissue (lapoma) or a Mammary (breast tissue) lump. What is it? What should I do?
Those are the most common tumours – the mammary mass is sadly probably more likely. I’d recommend getting it checked by your vet who can pull out a few cells with a needle and see how aggressive it is; fortunately, surgery on rats to remove these tumours is fairly routine these days, and once removed, they don’t usually come back.
My rat woke up one morning and poof, a tumor or a lump was on her back leg? it is hard, feels kind of like a semi circle in a way, and I can move it. Could you help me identify what kind of lump it is?
Not over the internet I’m afraid! The majority of lumps in rats are due to tumours, but other options include infected abscesses, cysts, or scars.
My rat literally woke up with a very large round lump, tumor, bubbble- what ever you want to call it- on his underbelly by his back leg. He was fine yesterday. No lump at all. It came out of nowhere. What is it?
Without examining it properly, it’s very hard to say, but if it really came up that quickly, it’s most likely to be an inflammatory lesion: potentially, an acute inflammatory response to an infarcted tumour (when a tumour outgrows part of its blood supply and part of it dies); or an abscess. Either way, I’d definitely advise a vet check!
My rat has a big lump. By reading this article I think it is lipoma The vet are all closed in our area and that lump is getter bigger. Do you have idea/anything to make him feel better? it doesn’t seem bother him but he is having hard time to walk since it’s getting bigger
There’s not a lot that can be done for a mass like that except removing it – and that need to balance against the suffering from the growing mass, and the potential complications from surgery. I would suggest finding a vet who can examine it as it may be a more malignant form that it immediately appears, but unfortunately, the options really are remove or “wait and see”.
The hard lump on my pet female, located by her groin, started oozing blood this morning. Should I euthanize her right away?
It depends exactly what’s going on; in many cases even ulcerated tumours can be successfully surgically removed, but it does depend whether tumour necrosis, primary tumour breakthrough, or trauma is the cause of the bleeding.
I have a rat with a small hard lump. It just appeared and it doesn’t seem to be affecting him. Is there anyone who knows what type of lump it possibly could be? I dont know his age properly but I’m guessing over a year at least
Lumps in rats are usually either tumours or, more rarely, abscesses. Hard lumps are typically tumours, often mammary (breast cancer – even in male rats); however, fortunately, if caught early they are usually curable with surgery to remove the mass.
My rat has two lumps on her body. One is small the other is pretty big and is loosing hair around it and it is popping out and looks red and bubbly.
That’s not nice – it sounds like it’s what we call ulcerated. I think that’s definitely time for the vet! Most tumours in rats can be removed surgically, and although the anaesthetic is a risk, it sounds nasty enough that it’s worth getting it seen to!