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Pet Rats/Tumor, Abscess, or Cyst and What to do


Robin 1
Robin 1  

Robin 2
Robin 2  
Hey Irene, this is my first time writing in a question to anyone. Let's get down to business. My rat Robin has sprung a mass overnight (it seems. I honestly do not remember it being there yesterday or the day before) but this thing is huge. It is on his side, drags a bit, but doesn't seem to interfere with anything. He's always been a hopper and continues to do so, move and run fine, eat and drink fine, and expunge waste perfectly fine. The mass seems to be on skin level, not under, as the mass moves when pulled taught, instead of the skin moving around it (that also didn't bother him). That would usually suggest a cyst or abscess, but I have never seen one this size at all. I wanted a second opinion before I try bugging my mom into taking him to the vet. I've never had this happen to any of my rats before. If it is a cyst or abscess, the idea of lancing and draining my fur baby makes me squeamish.

Rachael, I want to first apologize for responding so late...I have been ill for a week.  A tumor and an abscess/cyst feel generally the same, usually soft and just under the skin so it can be rolled around with your fingers.  The difference is that tumors are fairly slow-growing and won't just "appear" overnight and get this large this quickly.  A tumor will generally grow from pea-size to golf-ball size in about a month or two.  Because it appeared and grew this quickly leads me to believe it has to be an abscess.  I myself would not mess with lancing it either.  It would be traumatic for you and your rat, extremely messy and foul-smelling (especially due to its current size), aside from even being able to hold him still to perform this...good luck.  No, I highly recommend having a vet who is experienced with small animals (exotics) confirm the abscess and then lance it in the clinic.  The vet would likely prescribe antibiotics to help prevent infection as well.  

I hope this helps and that you will be able to take him to have this professionally removed.  Please let me know if I can answer anything else for you and I promise that the next time you won't have to wait so long for an answer as I rarely get sick for as long as I was this time, and am sorry that you had to wait this long to hear back.

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Irene Murphy


I can answer a variety of questions regarding adoption and care of pet rats throughout their lifetimes, including questions about their health and well being, temperment, diet, bedding, cages, toys, etc. I will try to answer your questions to the best of my ability in a timely manner and I have an abundant amount of resources to help me to help you with your pet rats. I love rattie pictures, so include pics with your question if you can. You may ask me medical questions, but please be advised that I am not a vet. I may use my resources to answer some medical questions, however, I will need to refer you to your local vet with medical questions that I feel I am not qualified to address.


I have been a huge rat enthusiast for many years. Since becoming a rat owner, I have educated myself in all areas of pet rats from every resource I could find including the internet, books, conversations with local exotic vets, as well as several local rat breeders.

I have a college degree but not in the area of animals. I have obtained my extensive experience and knowlege of pet rats all on my own because in my eyes, pet rats are the most interesting and fascinating creatures you can ever imagine to have as pets. I also am saddened by how mislabeled and misunderstood these amazing and extremely smart animals are by the majority, and my mission in life has become to educate and change as many people's perceptions of rats as I possibly can.

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