Hi, GB and Lori - A bruise that suddenly appears on your breast for no reason can possibly be a symptom of a rare form of breast cancer, inflammatory breast cancer. Keep your eye on it; if it doesn't disappear (or at least start to fade and become less noticeable) within a week or so, best to call the doctor. OR if it gets worse; if your breast seems infected (hot, red, swollen, painful, itchy), then see a doctor ASAP, OK? Good luck to both of you - PJH

As PJ says, an apparent bruise on the breast that doesn't heal could be a symptom of inflammatory breast cancer (IBC), especially if you have swelling, warmth, and skin dimpling.  Don't panic yet because IBC is rare.  If you are taking a medicine that thins the blood (including some herbs and vitamins like Vitamin E) you may find yourself bruising even when you don't remember an injury.  Anti-inflammatory pain killers like aspirin and ibuprophen make me bruise very easily, and I often don't remember an injury.  If this doesn't heal like a normal bruise, or if you find yourself with frequent bruises and no remembered injury, call your doctor.