My Dwarf Hamster has sudden swelling

[Hoyzar]

About a year ago I got a dwarf hamster, who gave birth several weeks later, she currently lives with one of her daughters and the other pups are in separate cages. She seemed to have no health problems until recently when I noticed a bump underneath her right front leg. I didn't pay much attention at first because I thought she was fighting with her daughter. A few weeks later I noticed the bump had become larger, but the hamster didn't show any difference in behavior. She is eating well and she'll run on her wheel and let me hold her.

The swelling feels soft and is about the size of a peanut (no shell). I'm wondering if it is an infection from a bite would or something worse? Also if I could treat this on my own and if I need to separate the hamster from her daughter?

[Aleda M Cheng, D.V.M., C.V.A]

I don't know how old your hamster is but it could be an abscess, or infection, or something worse, like cancer if your hamster is older.  I would take her to a vet to be definative.  Your vet could perform a fine needle aspirate by sticking a very tiny needle in the mass and if pus comes out it is an abscess, if something else comes out the substance can be sent to a pathologist for definative diagnosis.

[Hoyzar]

Oh, I forgot to add that. The hamster mentioned just turned 1 about 2 weeks ago. It might be cancer like you said because she is older. I'm concerned about how common is cancer in older hamsters? Because her pups are turning one in a few weeks.

Thank you for your help, I'll try to take her to the vet to see what it is.