Periductal mastitis/duct ectasia.

Periductal mastitis/duct ectasia affects major breast ducts and is poorly understood. A variety of different terms have been used for this condition and these probably reflect different stages in one disease process. It appears to be responsible for 1-2% of all symptomatic breast conditions. Although the incidence is higher in postmortem studies, much of what is included as so-called "periductal mastitis" or "duct ectasia" in these studies is duct dilatation, which occurs as part of normal breast involution. Periductal mastitis appears to be the primary condition with duct ectasia being the outcome. The cause of this periductal mastitis is uncertain, although bacteria, particularly anaerobic organisms, appear to play some role. Clinically, this condition can present with noncyclical mastalgia, nipple discharge, nipple retraction, a subareolar breast mass with or without overlying breast inflammation, a periareolar abscess, or a mammillary fistula. Antibiotics effective against the organisms isolated from this condition are effective in resolving periareolar inflammation and are useful when combined with surgery in mammillary fistula.