question: what are some of the most common diagnosis for a  painless rib tumor in a 15 year old?  my friends son has one and shes worried sick that it could be malignant.  but from what Ive read chondroma would be a more common diagnosis for rib tumors.  hes having a biopsy this week, but I was just wondering as Im trying to prepare myself for what it could possibly be.  any insight you could share would be great! thanks so much.