I had a open heart bypass surgery years ago . About a year ago, i noticed something like a protruding bone growth in the meddle of the sternum. At about 8 months ago, it was just a 1/4 of an inch diameter, rounded top. Today it seemed to have changed its shape. It became a little tilted like a shark s fin, and a little knife edge shape on the straight vertical side. sometime it seem like needle pushing the covering skin. What could it be. Does it need to be operated on. Thank you. email. johnny. YYYY@YYYY