Hi There, I Was Between 4 And 8 Yrs Of

hi there, I was between 4 and 8 yrs of age and I had a hard mass taken from the heel of my foot now I'm 48 yrs of age and the mass on my foot has come back I am asking why do I need to have a biopsy?, its the same thing from what ever it was in the 70's I had a MRI and an x-ray. They still don't know what it is, do you have any suggestions