The term nonpuerperal mastitis describes inflammatory lesions of the breast (mastitis) that occur unrelated to pregnancy and breastfeeding. It is sometimes equated with duct ectasia, but other forms can be described. Types
Duct ectasia—periductal mastitis complex
Duct ectasia in the literal sense (literally: duct widening) is a very common and thus rather unspecific finding, increasing with age. However, in the way in which the term is mostly used, duct ectasia is an inflammatory condition of the larger-order lactiferous ducts. It is considered likely that the condition is associated with aseptic (chemical) inflammation related to the rupture of ducts or cysts. It is controversial whether duct dilation occurs first and leads to secretory stasis and subsequent periductal inflammation or whether inflammation occurs first and leads to an inflammatory weakening of the duct walls and then stasis. When the inflammation is complicated by necrosis and secondary bacterial infection, breast abscesses may form. Subareolar abscess, also called Zuskas disease (only nonpuerperal case), is a frequently aseptic inflammation and has been associated with squamous metaplasia of the lactiferous ducts. The duct ectasia—periductal mastitis complex affects two groups of women: young women (in their late teens and early 20s) and perimenopausal women. Women in the younger group mostly have inverted nipples due to squamous metaplasia that lines the ducts more extensively compared to other women and produces keratin plugs which in turn lead to duct obstruction and then duct dilation, secretory stasis, inflammation, infection and abscess.
Because it is so rare it may be sometimes confused with comedo carcinoma of the breast although the conditions appear to be completely unrelated. == References ==