pet rat with lump

our 2 1/2 year old pet rat has a lump on his side. the lump is firm but squishy. he still acts normal and doesn't seem like it bothers him but we are concerned because we don't know the cause. any advice or help would be greatly appreciated. thank you.

Hello - rats do have a tendency to get lumps I am afraid, and there are as many types of lump that can appear on a rat as on any other species.  The presence or absence of pain doesn't help very much to distinguish between lump types.  Always check that a lump is not , for example, normal anatomy by feeling to see whether they are the same on both sides.  When they are not the same on both sides, it is fully recommended that you speak to your vet.  Here is an article that Rachel Hinks wrote on the subject. https://vethelpdirect.com/vetblog/2021/03/14/my-rat-has-a-lump-will-it-go-away-if-i-leave-it/ Wishing you and your boy all the best from here