MY dad has a weird lump on his elbow?! Please help?

OK my mum told me to look up on my computer what i could be. And there's so many things I'd have to scrawl through before I found anything similar, so I'll ask on here. It's a extra lump on his elbow bone, the pointy one when you bend your arm. It looks like extra bone growth but it's all squishy. It hurts aswell. Do you have any idea what it could be? I can emal a picture if you want, but I can't atm as my hpone is chargin. Thankyouu