During lactation, or at other times with dermatologic conditions that allow cracks and fissures to form in the skin of the nipple, infectious organisms can invade into breast and result in acute inflammation, and this may progress to breast abscess formation. The most common organism is Staphylococcus aureus. Organization with fibrous scar formation around the abscess can mimic a carcinoma on physical examination, by mammography, and grossly.