4yr old Lump on rib cage

I noticed a boney lump on my 4 yr old daughters left rib cage about 1cm in diameter.  I took her to the doctor the next day and the doctor thought she may have broken her rib so she sent us down for an xray. No Fracture... Then she send us down for blood work.  The lump is on the second or third rib bone from the top, boney feel and non mobile, no discoloration in skin.  We are meeting with a pediatric surgeon next week. The blood work was fine.. Just a little anemic. Otherwise she is very healthy.  Do you think this is anything?  What might this be?? The dr kept referring to it as a Mass.

Any advice would be appreciated.