Hi there!
Well, without a detailed clinical evaluation it would be difficult to determine the cause of the lesion or give an opinion regarding its nature. Possible causes that may need to be considered include growths from the bone/ surrounding connective tissue etc. If your doctor believes it not to be anything to worry about, it is likely to be a benign lesion and best left as such unless for cosmetic reasons. I would suggest discussing the situation and the suggested management plan in detail with your treating doctor.
Hope this is helpful.
Take care!
?? i thought this forum was for advise