What Causes Unhealed Bruise On Calf?

I have an unhealed bruise on my calf, about the size of a quarter. It s darker in color and has a firmer feel to it compared to the other skin around it. I ve had it for almost a year. I believe I first got the bruise while biking, but it is not healing. I have no other troubles with bruising or healing of cuts/scrapes. Is there a concern if a bruise does not go away?