The term nonpuerperal mastitis describes inflammatory lesions of the breast (

mastitis Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...

) that occur unrelated to

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

and

breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that bre ...

. It is sometimes equated with

duct ectasia Duct ectasia of the breast, mammary duct ectasia or plasma cell mastitis is a condition that occurs when a milk duct beneath the nipple widens, the duct walls thicken, and the duct fills with fluid. This is the most common cause of greenish dischar ...

, 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,

is an inflammatory condition of the larger-order

lactiferous duct Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland. When lactogenesis occurs, under the influence of hormones, the milk is moved to the nipple by the action of smooth mus ...

s. It is considered likely that the condition is associated with aseptic (chemical) inflammation related to the rupture of ducts or

cysts A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...

. It is controversial whether duct dilation occurs first and leads to secretory

stasis Stasis (from Greek στάσις "a standing still") may refer to: * A state in stability theory, in which all forces are equal and opposing, therefore they cancel out each other * Stasis (political history), a period of civil war within an ancient ...

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 Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

and secondary bacterial infection,

breast abscess Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...

es may form. Subareolar abscess, also called Zuska's 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 Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up Scale (anatomy), scales, hair, Nail ...

plugs which in turn lead to duct obstruction and then duct dilation, secretory stasis, inflammation, infection and abscess. This is not typically the case for women in the older group; in this group, there is likely a multifactorial etiology involving the balance in

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

progesterone Progesterone (P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the majo ...

and

prolactin Prolactin (PRL), also known as lactotropin, is a protein best known for its role in enabling mammals to produce milk. It is influential in over 300 separate processes in various vertebrates, including humans. Prolactin is secreted from the pi ...

. Treatment of mastitis and/or abscess in nonlactating women is largely the same as that of lactational mastitis, generally involving antibiotics treatment, possibly surgical intervention by means of

fine-needle aspiration Fine-needle aspiration (FNA) is a diagnostic procedure used to investigate lumps or masses. In this technique, a thin (23–25 gauge (0.52 to 0.64 mm outer diameter)), hollow needle is inserted into the mass for sampling of cells that, aft ...

and/or

incision and drainage Incision and drainage (I&D), also known as clinical lancing, are minor surgical procedures to release pus or pressure built up under the skin, such as from an abscess, boil, or infected paranasal sinus. It is performed by treating the area with a ...

and/or interventions on the lactiferous ducts (for details, ''see also'' the articles on treatment of mastitis, of breast abscess and of subareolar abscess). Additionally, an investigation for possible malignancy is needed, normally by means of

mammography Mammography (also called mastography) is the process of using low-energy X-rays (usually around 30 kVp) to examine the human breast for diagnosis and screening. The goal of mammography is the early detection of breast cancer, typically through ...

, and a pathological investigation such as a biopsy may be necessary to exclude malignant mastitis. Although no ''causal'' relation with breast cancer has been established, there appears to be an increased statistical risk of breast cancer, warranting a long-term surveillance of patients diagnosed with non-puerperal mastitis. Nonpuerperal breast abscesses have a higher rate of recurrence compared to puerperal breast abscesses., abstract There is a high statistical correlation of nonpuerperal breast abscess with

diabetes mellitus Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

(DM). On this basis, it has recently been suggested that diabetes screening should be performed on patients with such abscesses.

Granulomatous mastitis

Characteristic for granulomatous mastitis are

multinucleated giant cells A giant cell (also known as multinucleated giant cell, or multinucleate giant cell) is a mass formed by the union of several distinct cells (usually histiocytes), often forming a granuloma. Although there is typically a focus on the pathological ...

and

epithelioid histiocyte According to a common point of view epithelioid cells (also called epithelioid histiocytes) are derivatives of activated macrophages resembling epithelial cells. Structure and function Structurally, epithelioid cells (when examined by light ...

s around lobules. Often minor ductal and periductal inflammation is present. The lesion is in some cases very difficult to distinguish from

breast cancer Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or ...

Comedo mastitis

Comedo mastitis is a very rare form similar to granulomatous mastitis but with

tissue necrosis Necrosis () is a form of cell injury which results in the premature death of Cell (biology), cells in living Tissue (biology), tissue by Autolysis (biology), autolysis. Necrosis is caused by factors external to the cell or tissue, such as infec ...

. Because it is so rare it may be sometimes confused with

comedo carcinoma Comedocarcinoma is a kind of breast cancer that demonstrates comedonecrosis, which is the central necrosis of cancer cells within involved ducts. Comedocarcinomas are usually non-infiltrating anintraductaltumors, characterized as a comedo-type, h ...

of the breast although the conditions appear to be completely unrelated.

References

{{Diseases of the breast Inflammations Breast diseases