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Pet Rats/Tumor..cyst..abscess???


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QUESTION: Hi Debbie,

It appears my male rat Ziggy, who is a little over two years old, has developed an odd lump on his side. I've already read the pages on your website regarding determining whether the lump is an abscess, tumor, or cyst..but I still can't figure out what it is. A few days ago I noticed he had very raspy breathing, so I took him to the vet and they prescribed Baytril and it surprisingly cleared up overnight. The next morning his lungs sounded completely normal, but I am continuing the Baytril of course. I recently gave him a treat of Nutro Natural Choice weight management canned food for the first time and I picked him up a few minutes later (after he gorged out on his snack) and noticed a large bulge protruding from his middle right side. I figured maybe he was just "full" and put him back. I checked on him again many hours later and the bulge was still there. I know it is not a blockage because he has pooped since the feeding and continues to eat and drink normally. He doesn't appear lethargic or any less active than usual. The lump is relatively soft and moves when he scratches almost like a ball of fat. I'm guessing this means it moves with his skin. It does feel a bit hard in the center. From the pictures on your website, I am 99% sure it is not a cyst...but it would be odd for a tumor to just show up in a matter of hours. I'm going to include a picture because maybe that can help you. Thanks so much.

ANSWER: It sounds like you intended your question for Debbie, but since it came to me, I'll go ahead and help you if you don't mind.  As you probably know from reading Debbie's website, tumors of that size do not suddenly appear overnight (unless it's been there and growing for several weeks now and you just didn't notice it).  If it's a tumor, it would be about a month or so old at this size.

I've had many female rats develop mammary tumors so I have experience in this area.  Mammary tumors, though not as common with boys, and abscesses often feel similar and move freely when held and massaged with your fingers.  

Assuming it truly was not there the other day and now it's this large, it is likely an abscess (let's hope).  

I still would recommend taking him to the vet to get an accurate diagnosis.  Hopefully, your vet is well trained in treating rats.  If he determines it's an abscess, he can drain it right there on the spot.  If it's a tumor, he can suggest removal.

I hope for the best for you little guy.  If you have additional questions, please do contact me.

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Thank you so much for your response. Do you think he could be "backed up"? I've been throwing this possibility around because he's had only one bowel movement since the lump appeared and the poop appears to be very dark and each one is much longer than usual.. I'm really doubting its a tumor because I have been keeping such a close eye on him and handling him multiple times every day to listen to his breathing and his lungs. Have you had any experience with this? I've had multiple rats in the past, but never experienced anything like this.

ANSWER: So sorry for the delay in my response. Yes, it is a good possibility that he could be backed up.  If he is blocked/impacted in the abdomen, that is worse than constipation.  It can be very serious.

Not to worry you, but just to make you aware, bloating in the abdomen can also be a sign of heart trouble (cardiomyopathy) although he would have other signs such as rapid heart rate and tiring easily.

I strongly recommend a vet visit as soon as possible.  In the meantime, you can try offering him baby food prunes to see if that loosens his stools and makes him go more frequently.  I don't know how much experience your vet has with treating rats, but I've heard of less-than-knowledgeable vets give rats an enema for blockage...if your vet suggests this, please do not allow him to do it.  There is medication that can be given for blockage.  It is called Senokot, and I believe can be purchased over the counter.  Here's a link to information about it:

If by chance you don't believe your vet is adequately trained to treat rats, let me know what major city you live in or nearby and I can find an exotic vet or one that has experience with treating rats near you.

Please update me if you will on how your boy is doing.

By the way, one of my first female rats was named Ziggy :)

---------- FOLLOW-UP ----------

QUESTION: Hey Irene,

I took little Ziggy to the vet two days ago and she aspiriated the growth with a needle & performed an in-house cetology. She only saw a tiny bit of blood (which she assured me was normal) and a bunch of FAT cells. Haha, she diagnosed it as a rare rat lipoma, the kind dogs usually get. She offered to send it to a lab for further research (for a whopping $100) and I declined. Looks like I just got REALLY lucky. It hasn't grown any larger and his stool is normal once again. She also let me know that his lungs have cleared up completely :)

Ziggy is just an awesome name for ANY rat. Thank you so much for your help and advice. I really appreciate it. He's definitely still got some fight in him!

Thank you for updating me...I always welcome wonderful news!  So glad to hear it's nothing serious and that Ziggy's other conditions have cleared up.  You DO have a little fighter there.  I can tell how much you love him.

I've never had a dog and don't know much about them...have never heard of a lipoma, but I'm going to research it right now so I can educate myself if it comes up again in rats.

I agree that Ziggy's a great name (I was thinking of Ziggy Marley when I chose the name).  Thought it'd be cute for a girl.  My first rats were Ziggy and Zoey...I liked how those 2 names sounded together.

Please contact me again if you need any help with your ratties.  

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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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