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Ask Dr. B. Your Own Question
Dr. B.
Dr. B., Board Certified Veterinarian
Category: Vet
Satisfied Customers: 22461
Experience:  General practice veterinary surgeon with extensive experience in a wide range of species.
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I wanted some advice on small lumps found on my guinea pig.

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I wanted some advice on small lumps found on my guinea pig. The advice I have already been given by a vet was confusing and unhelpful.

Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.

Where are the lumps located?

How long have they been present?

Are they soft, firm, fluidy, sore or warm to the touch?

How is Marmite?

Has her vet tried treating them with anything?

Can you take a photo of these ? If you can do so and post them online, this will let me see what you are seeing. To post them, you can either use the wee paper clip on the tool bar above your text box. Or if you cannot see that on your computer/phone, then you can post them on an alternative site (ie Flickr, Photobucket, imgur, etc) and paste the web link here for me to check.

Customer: replied 2 years ago.

Thank you for your answer. The lumps are in what I would call Marmite's armpit area on his front right leg. They have been there about two months (I saw the vet about a month ago now for the first time). Since then one of them has got slightly larger. They are firm but you can move them around a bit and they don't hurt him if you touch or squeeze them slightly. Other than that he is very well and the vet said in good health, he is eating and drinking as normal and is very active. The vet did say they could take a sample to see what they were but advised a monitor them for a little bit. They wouldn't really be visible in a photo if that makes sense. My main concern is I don't want to subject him to surgery or anaesthetic if it's not needed and he's otherwise happy. Thank you.

You are very welcome Zoe,

Now as I am sure you can appreciate, lumps of this nature can be caused by a range of agents. With the longer term presence of these lumps, we would assume they are not related to trauma, hematomas (blood blisters), or secondary to allergic reactions (ie insect stings). This means we have to consider chronic abscesses, scar tissue, cysts, fatty lumps (lipomas), benign growths, and worrisome tumors. And I do have to note that if one is present in his armpit, then that could actually be an enlarged lymph node reacting to the growth on his leg.

With all this in mind and trying to do the best for your wee lad, it would be ideal to have his vet sample the lumps at this time. We don't really want to wait any longer if these are getting bigger at all. The reason is because Marmite only has so much skin and surrounding tissue to the lump (especially with the leg). And the bigger the mass gets, the more likely he will get to a stage where there are no treatment options and your vet tells you there is nothing that can be done. Therefore, while I appreciate that you are not keen for surgery (which is fair enough), it is best to know what we are facing sooner rather then later. Especially as finding something we can treat now could give him an overall better prognosis.

In regards ***** ***** the nature of these growths, this can be done via fine needle aspiration (FNA). This is where the vet uses a needle to harvest cells from the mass (and often the do not need any sedation for this). If the remove pus, then this tells us that there is infection present and antibiotics can be dispensed to clear it. If blood or blood stained fluid is removed, then a cyst would be more likely (which can be drained or removed for cosmetic purposes). If fat is extracted, then a lipoma would be likely and again surgery would be indicated only if the lump was stretching the skin or causing bother. Otherwise, if the above are not found, then the cells they harvest can be stained and the identity of the nature of the mass can be determined and whether it is something that is concerning or needs more serious treatment.

Overall, if the lumps are getting bigger, then we don't want to just monitor anymore. Instead, we need to be proactive and know what we are facing with Marmite. So, do consider having the lumps sampled at this point. Hopefully, we will find one of those treatable options I noted and be able to sort this for him. But if it is found to be something sinister, then its best to know now so that you can discuss all the potential treatment options with his vet and give Marmite the best chance here.

I hope this information is helpful.

If you need any additional information, do not hesitate to ask!

All the best,

Dr. B.


If you have any other questions, please ask me – I’ll be happy to respond. Please remember to rate my service once you have all the information you need as this is how I am credited for assisting you today. Thank you! : )
Dr. B. and 2 other Vet Specialists are ready to help you
Customer: replied 2 years ago.

I just wanted to say thank you for your advice and help, I'll book an appointment for Marmite this week.

Kind regards,


You are very welcome, Zoe.

That sounds perfect. Smile
All the best for wee Marmite and do let me know how he gets on.

Have a great day,
Dr. B.