Benign breast pathology includes a wide and heterogeneous spectrum of lesions that can be clinically palpable, detectable only with instrumental means or, finally, occasionally available during biopsies or surgical excisions. Most of these lesions result from aberrations of the normal development process, from cyclic hormonal activity and from involutionary or inflammatory phenomena.
These injuries account for about 90% of the conditions that lead a woman to a breast examination. In women, e.g. it is possible to find supernumerary breasts or their residues along the "milk line".
Breast residues can undergo pathological changes.
Relatively symmetrical even organs, functional units: lobes (on average 27 for each gland) connected by galactophoric ducts to the nipple. The ducts branch into segmentaries and subsegmentaries and end in the ductulo-tubular terminal units. The nipple is covered with an epidermis rich in melanocytes.
Acinar glandular structures
Vi si osservano le cellule di Toker,
considerate analoghe degli elementi di rivestimento dei dotti
The breast lobes are of three types:
- larger or mainly present in the super-external quadrant;
- of intermediate dimensions
- smaller in size
The ducts are covered with a layer of cubic or cylindrical epithelium,
resting on a layer of myoepithelial cells with a basement membrane.
The berries are missing in the male breast, appear at puberty and the secretory cells undergo cyclic modifications induced by hormones
steroids.
A breast duct has a multi-layered epithelium of the galactophoric ducts which gradually gives way to the double-layered cylindrical epithelium.
The luminal epithelial cells of the ducts (in pink), then, there are the myoepithelial cells that are located between the epithelial cells and the basement membrane; in purple the cells that make up the berries. During pregnancy the berries reach full development and at the end of pregnancy the cells show intense phenomena of apical secretion.
In post-menopause, the breast undergoes fibro-fat involution.
The breast has lymphatic drainage. Most lymphatics from the mammary gland drain into the axillary lymph nodes.
The sap of the internal quadrants may partly flow counter-laterally due to the presence of anastomosis.
Part of the lymph coming from the deep portions of the parenchyma can flow into the internal mammary chain.
Non neoplastic lesions
Benign tumors
Precancerous lesions
Malignant tumors
Cysts (simple, complex, complicated), benign calcifications, ductal ectasia, mild ductal hyperplasia with increase in n. ductal epithelial cells up to 4.
Adenosis, fibroadenomas and fibroepithelial lesions ( tubular adenoma, phyllodes, hamartoma ), usual ductal hyperplasia (increase in the number of ductal epithelial cells beyond 4), myopepithelial lesions (adenomyopithelioma, myofibroblastoma, pleomorphic adenoma), sclerosing lesions (sclerosing adenosis, radial scar), papillomas (solitary, multiple, juvenile papillomatosis, nipple adenoma)
flat epithelial atypia (or DIN 1 a), atypical ductal hyperplasia (or DIN 1 b), atypical lobular hyperplasia (or LIN 1)
amyloidosis, congenital anomalies, abscess, hematoma, galactocele, gynecomastia, liponecrosis, Mondor's disease, mastodynia, diabetic mastopathy, sarcoidosis, tuberculosis
Non-neoplastic lesions are generally represented by inflammatory and regressive diseases; we have fibrotic processes ; sclero-elastotic stromal lesions; hyperplastic diseases : cystic disease and adenosis
As regards inflammatory and regressive pathologies, we have inflammatory lesions during pregnancy and breastfeeding:
- acute mastitis,
- abscess,
- breast infarction,
- galactocele
Under these conditions, the duct galactophore undergoes inflammation which determines an abscess collection, periductal mastitis, plasma cell mastitis or obliterative mastitis. The duct affected by the process is surrounded by an inflammatory infiltrate and with the lumen obliterated by macrophages and inflammation.
In obliterative mastitis the duct galactophore is occluded, replaced by fibrotic material, surrounded by the degenerative thickening of the elastic layer which is thickened (elastosis).
Sclero-elastotic lesion of the stroma
In young women the fibrous stroma is abundant; focal fibrosis areas can result from inflammatory processes.
Focal sclero-elastotic lesion: it results from ductal obliteration and inflammation
Chronic . It can create alarm because clinically, mammographically and macroscopically indistinguishable from a carcinoma
-Ductal ectasia and plasma cell mastitis
- Lipophagic granuloma
- Granulomatous lobular mastitis
-Mastopathy in type I diabetes: fibrous nodules and lymphocytic infiltrates a
possible autoimmune pathogenesis.
Benign lesions are divided into:
- Cystic breast disease
- Adenosis
Once grouped in the generic term fibro-cystic disease they could today be better described, for the clinician, with the formula breast irregularly nodular. These injuries are dominated on the plane strictly numerical, from cysts.
These are lobulary involutional processes that manifest themselves in the form of macrocysts (diameter such as to manifest themselves as a palpable mass) or microcysts (evidenced only by ultrasound. They are usually seen in pre-menopausal women between 35 and 50 years of age (but even more if they are taking hormone replacement therapy). They can also appear in a few days, mainly due to the effect of hormonal cyclical variations, thus causing tension pain. Cysts are not trivial conditions for many reasons.
Cystic disease is frequent in fertile age, related to early focal
involutionary phenomena. The role of sex hormones has not been clarified. It is
characterized by cystic dilatation of the terminal ducts and berries, which can
give the palpatory finding of "hunting shot".
Localization of lesions on the periphery of the gland The macroscopic aspect is
of "small cluster cysts". The cysts can be lined with epithelium with apocrine
metaplasia, sometimes found in papillary formations.
Apocrine cells show eosinophilic granular cytoplasms, secrete
Prolactin-Inducible Protein (PIP), are negative for ER and PG receptors, while
expressing androgen receptors. Ductal hyperplasia and stromal fibrosis coexist.
Finally, in cystic disease, it is possible to appreciate calcifications,
possible depositions of calcium salts (phosphates or oxalates), recognizable
mammographically if greater than 100μm in diameter.
We can have variegated lesions that proliferate, without degenerating.
Fibroadenomas and hamartomas are usually benign lesions. Phylloid tumors show a spectrum that includes malignancy. Sclerosing lesions are benign, but can be part of in situ neoplasms and invasive carcinomas. Papillary lesions belong to an expressive variety that extends from the benign to the malignant. With these assumptions it is understandable why even proliferative lesions without atypia deserve scrupulous clinical analysis and appropriate surveillance over time.
Numerical increase in the glandular structures of the breast; we can have nodular, sclerosing, micro-glandular adenosis
Fibroadenoma is frequent, young women; it is characterized by a single or less frequently multiple nodule, movable, of increased consistency. Its evolution is linked to sex hormones and post-menopausal invocation.
The giant shape is rare, its appearance is homogeneous to the cut; the juvenile variety can have intracanalicular or pericanalicular development. Fibroadenoma is a lesion in the biphasic ductulo-lobular terminal unit that is made up of cellular and stromal elements: the epithelial component consists of areas of heximil-ductal glandular-like tissue delimited by typical cuboidal or columnar cells; the stromal component consists of connective tissue with a variable content of collagen and mucopolysaccharides. The genesis of fibroadenomas is probably linked to a greater sensitivity to estrogen, but the causal relationship with cyclosporin A in kidney transplant women is also known (in this case they are often multiple and bilateral).
Sometimes fibroadenomas contain cysts, sclerosing adenosis, calcifications and papillary apocrine modification (cells with eosinophilic cytoplasm): they are then defined complexes, an attribute that associates them with a slight increase in the risk of carcinoma. Macroscopically, they appear well circumscribed, with pseudocapsules, distinct from the breast parenchyma, oval or rounded (sometimes plurilobulate ) and, when cut, grayish-white complexion.
Dimensions vary from 1 to 3-4 cm, if larger than yes talks about giant fibroadenomas. They occur during the fertile life, especially before the age of 30, but a variant (juvenile fibroadenoma) may appear between 10 and 18 years of age and is characterized by its large size (up to 10 and more cm, with ample breast occupation) linked to a greater glandular component and a richer stromal cellularity.
Ductal adenoma
Intraductal papilloma
Fibroepithelial tumors: Fibroadenoma and phyllodes tumor
Central localization (of the great ducts), or peripheral
Intraductal papillomatosis
We distinguish between a central and peripheral papilloma, it can manifest itself with the discharge of secretions from a single nipple.
These are rare conditions that occur mainly in the latter fertile and post-menopausal life phase (average presentation age 48 years).
Although they are not yet well understood and although they are benign conditions, their importance lies in the possible association with carcinoma, especially where atypia coexist. In general, solitary papillomas are found in the galactophoric sinuses near the nipple, multiple ones lie in the depth of the ductal system.
They usually grow in ducts of greater caliber and proximal to the nipple 2-5 mm, rarely conspicuous (up to 3-5 cm). When cut, they appear crumbly and can be joined to the wall of the duct by a peduncle, or sessile.
Under the microscope, the multiple papillary, arborescent formations, coated by an epithelium of cuboidal or columnar cells, each with one fibrovascular stem; myoepithelial cells are present, arranged between the stem and epithelium.
If they experience ischemia, papillomas may occur with serum hematic discharge from the nipple . When the lesion shows a prevalent stromal architecture we speak of sclerosing papilloma.
Another variant is the intracystic papilloma , the result of a particular dilation of the duct that welcomes it or of its growth inside a cyst. All solitary papillomas can host areas of ductal hyperplasia with or without atypia or intraepithelial neoplasia (DIN, events that affect an increased exposure to cancer risk
Wide spectrum of lesions with predominantly benign behavior.
Florid stromal component, epithelial component delimiting large virtual gaps that appear as leaf fissures on the cutting surfaces (hence the name)
Fast growth, large size
Malignant sarcomatous forms
The phyllode (or phylloid tumor, so called for the tissue arrangement with polypoid protrusions and slits that resemble the profiles of the leaves) originates, like fibroadenoma, from the intralobular stroma. It is therefore a biphasic fibro-epithelial lesion.
For this reason the hypothesis of its derivation from a fibroadenoma is supported. Pseudocapsulato, it has three histological variants:
benign (low grade), malignant (high grade) and border-line (intermediate grade).
The choice to identify an intermediate form depends on the difficulty sometimes encountered in distinguishing with certainty the benign forms from the malignant ones; the elements on which it is based this distinction is: the atypia of the stromal cells, the mitotic activity and the nature of the margins (circumscribed or infiltrative). Half of the shapes are low grade. Forty times less common than fibroadenoma, it usually appears 10-20 years later than the latter.
On clinical examination it looks like a stretched mass, quite soft and spent multidodular , but its occupation of the breast is very variable, which may also affect it in its entirety.