Help Strange Leg Problem!

[YaBoi]

hi!i have a 1 1/2 year old hamster:male Syrian long haired—and I noticed recently while taking him out to clean his cage that he has a large like about the size of the biggest ball in a game of marbles size lump(strange size scale but I’m not sure how to explain it) on his back left leg. It still has hair and is kind of “hard”but smooth. He sleeps constantly and that may be too old age but I’m worried. I’m not sure how long it has been there and it’s not super noticeable in a picture due to his long fluffy fur. I’m worried because I cannot make a vet visit for a few specific things but I want to know if this could be fatal or something awful. I’m scared and I want to have some more information please. He eats regularly and when taken out for excercise instead of becoming energized he falls asleep without regard to anything.thank you💙for any information you could give!and get back to me soon❤️

[cypher]

18 months is getting on in age but not that old for a Syrian so sleeping more may be a sign of something other than old age.
It's impossible to guess what the lump may be or what help he made need, try to find a way to get him to a vet if you possibly can.