Nonpuerperal mastitis

Types

Duct ectasia, in its literal sense of duct widening, is a common and nonspecific finding that becomes more frequent with age. As typically used, the term denotes an inflammatory condition of the larger lactiferous ducts, likely stemming from aseptic chemical inflammation after duct or cyst rupture. Whether duct dilation precedes secretory stasis and periductal inflammation, or inflammation first weakens the duct walls and leads to stasis, remains debated. When necrosis and secondary bacterial infection complicate the inflammation, breast abscesses may develop. Subareolar abscess, or Zuska's disease in nonpuerperal cases, is often aseptic and linked to squamous metaplasia of the lactiferous ducts. The duct ectasia–periductal mastitis complex affects two groups: young women (late teens to early 20s) and perimenopausal women. In the younger group, inverted nipples are common due to extensive squamous metaplasia that produces keratin plugs, causing duct obstruction, dilation, stasis, inflammation, infection, and abscess. For the older group, etiology is likely multifactorial, involving estrogen, progesterone, and prolactin balance. Treatment for nonlactating women resembles that for lactational mastitis, including antibiotics and possible surgical procedures such as fine-needle aspiration, incision and drainage, or interventions on the lactiferous ducts. Investigation for malignancy via mammography and possibly biopsy is necessary to exclude malignant mastitis. Although no causal link to breast cancer is established, an increased statistical risk warrants long-term surveillance.