Similar situation here. Except mine is "free floating" not attached to anything. Also mine is very hard and small like a BB. It is very hard to find and when I went to a doctor he couldn't find it, and subsequently didn't run any x-rays or ultrasound. He did however tell me that it is most likely hardened cartilage as the result of any possible trauma that may have been inflicted on the scrotum, for example getting kicked in the nutsack one too many times. I don't know if I buy this for he wasn't very efficient with his observations or diagnosis especially considering he didn't actually feel it for himself. That visit was over 12 years ago and the BB sized free floating ball hasn't grown in size at all nor has it caused me any pain or discomfort. It's just there.