Mastitis
Mastitis is an inflammatory process of one or more
breast segments (the upper left quadrant is most commonly
affected) that may or may not progress into bacterial
infection. It usually occurs in the second and third weeks
after delivery, and very rarely, after the twelfth week.4
Initially, the intraductal pressure rises due to milk stasis (a
plugged duct often is the precursor of mastitis), with
consequent flattening of alveolar cells and development of
spaces between the cells.