eek i found a lump on my rat

Question
hi,
  my rat female Bella has a lump on her genital area well its sort of in between the genitals and her leg (it sorta looks like she is a boy rat if that gives you a better idea of ware it is) i am going to take her to the vets(don't worry I'm not just trying to find out if theres a cheap option or anything).

i was just wondering if you could tell me what the chances are that its something bad but not life threatening or seriously bad, the lump itself is quite hard it doesn't seem to be painful (but as soon as they figure out that your trying to look at something they don't let you near them)its just smaller than a sprout(a medium sized one).

also i was wondering what are the chances of her needing surgery and if so what are the chances of it going wrong she  has just turned two but is in amazing shape healthy weight very active good appetite good diet (my rats probably eat better than me) plus she has never really had any other health problems,because if theres a high chance of her dieing in surgery then ill probably not opt for it as she isnt realy in any pain or affected by it and she is 2 which is the good half of a ratties life and id rather spend the rest with her (and the lump).

thank you for your time and just letting you know i know you cant give me exact answers on what it could be im just impatient and love my rats dearly and want to know the chances

thank you again god bless x  

Answer
 Lumps are very common on rats, and in a female it is usually a mammary tumor.  These tumors are usually benign, meaning they won't spread to more serious parts of her body, but they do often keep coming back after they are removed and will continue to grow and grow unless they are surgically removed.  Tumors don't cause any pain, but when they get really big they can make it uncomfortable for them to walk, and when they start dragging on the ground they can get ulcerated from the rubbing.

 Rats usually do fairly well in surgery, though there is always a risk with any procedure involving anesthetic.  The surgery gets more risky as the tumor gets larger, as the veins going to the tumor get bigger and have more of a risk of bleeding out, as well as the skin being harder to close since the tumor is so big.  If you're going to have it removed it's best you do it right away.  This doesn't mean the tumor won't come back, however.  Female rats, especially older rats, often continue to get tumors into their old age and it is up to you whether or not to continue doing the surgeries.  If they are in excellent health otherwise and you can afford it it is usually a good option, but once they start getting older and more decrepit it may not be worth the stress of the surgery.

 Well I hope that helps you; hopefully everything will turn out fine for your little girl!  Good luck!