Bloated bottom

Question
I just bought a larger black hamster today- i believe it is syrian. When i got home i noticed its bottom (under the tail) is very bloated, rather enlarged and just doesnt look right. The pet store said the hamster was a girl and anyways the bolding abdomen does not resemble testicles.

its it a tumor? please help- i dont know if this is normal.
THANKYOU for your help

Answer
A lot of pet stores don't separate their hams by gender, and don't train associates to properly identify them, so even though they may have thought it was a female, there's a possibility it could be a male. Testicles can vary in size and shape, from pea to peanut sized, but they tend to look like a buttocks. If your hamster has a single round lump, that may be an indication it does have a tumor. I have no pictures to show of what a males testicles should look like, but if the lump is hard, I would take it to the vet to be safe, testicles are not hard.