Lipoma or cancer? soft round lump on lower rib cage. three ribs up from the bottom left. movable, rubbery, on top of ribs, no pain, no color change.??

Need a biopsy: The best way to answer your concern is to have the lump examined and biopsied then wait for the pathologist's diagnosis

Benign: This sounds like a benign growth if it's quite moveable and has not changed in size or appearance over a long period of observation. However it's best to have your physician examine this lump to be certain. He/she will let you know if a followup exam in the future is advisable.