female rat with egg sized lump under left arm

Question
I have a wonderful 2 1/2 year old female rat.  She recently in just one weeks time developed a large egg sized lump under her left arm.  It seems to be getting bigger and she seems to pant at times like a dog.  She has also lost some fur on her back and on the lump.  Her nose seems to always be red and her tail seems to have what looks like dried blood (maybe from her nasal discharge?)  She is not sneezing.  She was eating okay until yesterday and now she won't each much at all.  She is extremely skinny and I can see her spine.  Wondering what I should do at this point.  My husband refuses to pay for surgery since she's an older rat.  So I'm wondering if I should put her to sleep or is this something that she can recover from.  I don't want to see her suffer and I just am not sure what these symptoms will bring in the future.  I appreciate any help you can give me.

Answer
Hi Karen

Sounds like your sweet rat has a mammary tumor. I would love to say its an abscess, and it still could be, but this is one of the many prime locations mammary tumors are found and they grow pretty fast, too.
Her age is also the prime age to get these nasty things. Usually after menopause, between 18 months and 24 months, the intact female rats estrus cycle stops and estrogen levels begin to elevate, sometimes at extreme rates. Estrogen levels being that high trigger the growth of mammary tumors and depending on the levels of estrogen, more than one may appear and they grow like wild fire. The good news is they are almost always benign and they are not invasive that they can invade internal organs and spread to them too. Instead, they are subcutaneous and are easily removed, so much so that they almost are "peeled" right off the rats skin and the recovery is really fast, even for a rat her age. In fact, age is NOT a disease, its simply a number and if your rat is otherwise healthy, having this removed she may live another year or more. I have had 3 year old rats undergo surgery for this and they lived on to be nearly 4 years old.  Maybe this will help hubby understand.
Anyhow, what your seeing as far as the red nasal discharge is called "porphyrin" and it is produced by the harderian gland behind the rats eyes. Porphyrin is normally used to lubricate the rats third eyelid but when they are stressed or sick, they produce more, often coming from the nose and eyes too, and they can get it on their fur and tail if they sneeze or groom themselves and they get it on the paws first and smear it around. Many people become alarmed thinking it is blood, but its not.
It is a good way for mother nature to let us know the rat is not well, however.
What the tumor will do if you remains intact is, it will become vascular, making its own blood supply by robbing your rat of hers. It will start to take the nutrients she is getting from her food and no matter how much she eats, she will drop weight like crazy. Eventually, her vital organs will not be able to work properly due to lack of nutrition (bascially she is skinny because she is becoming malnourished from this nasty tumor!!) no matter what she eats, the tumor is feeding from her.
What will eventually happen is the tumor will become too large and become necrotic and wont be able to support its own blood supply any longer and will start to become infected. If this happens, the tumor can abscess internally and the toxins will spill into her blood stream and sepsis occurs. This will end up causing death. However, often heart failure and kidney and liver failure cause death before sepsis due to the fact the rats body is so malnourished the organs can no longer be supported. Its sad and also I hate even telling people this, but its the truth. This is how it happens in a nutshell, beginning to end.
If she is still acting like herself and you dont plan on removing it,I would not put her down but only YOU can make this call. You know her better than anyone else and you know when your rat still has the spark of life in their eyes.
What I did was this......I had already paid for two surgeries on my old girl, Holly.  They grew back twice. THe third time I just said to he** with it and we let it go. SHe was a bit over 3 at the time. These tumors were the size of eggs and started to slow her down.She was all skin and bones.  I couldnt stand seeing her not be able to walk any longer and I took her in to put her to sleep. The thing was, she was still acting OK. She was eating like a champ, bruxing her heart out, grooming herself and grooming me too...she had all the spunk and spark as a younger rat had if not more. The vet said he cant do it either....so we said lets go for it and remove the two largest tumors she had (she had at least 4)
She was under for 90 mins. which is a long time for an old gal like HOlly, but she did great and she recovered fully. She lived on to be two months shy of her 4th birthday....and to think if I put her down when I was going to, I was ending her life too soon and she lived another 10 months which is great.
There are other alternatives other than surgery which is giving the rat injections of a hormone that stops production of estrogen and either halts tumor growth or slows it down totally. We did this with Holly since she had other tumors on her that the doctor let go during surgery because he didnt want her under anesthesia any longer than she was already.  The lupron also helped Holly along with surgery.

Last but not least, you can also do nothing at all. The decision is yours. It wont make you a bad rat owner either if you opt to do nothing.  keep her comfortable and happy best you can until she no longer seems to have a zest for life, that is OK too.  Thanks for taking the time to ask about the health of your rat. I can tell you love her and want what is best for her and for YOU, as well.  I will support you no matter what decision you make.