L27 - Pathology of the breast Flashcards
Definition of the breast
The breast is a modified sweat gland that develops into a complete functional structure in the female, but remains rudimentary in the male.
Major components of the breast
the skin
the subcutaneous adipose tissue
the functional glandular tissue.
Breast glandular tissue structure
The breast is divided into 15-25 lobes, each based on a branching duct system leading to the terminal duct-lobular unit which is the functional site of milk production. Each lobe is made up of 20-40 lobules:
Nipple -> lactiferous sinus -> lactiferous duct -> segmental duct -> terminal duct-lobular unit (terminal duct -> lobule -> acini)
Lining of breast acini
each acini lined by epithelial cells and a basal myoepithelial cell
stages of alteration of breasts
development and puberty
maturation and differentiation
lactation (** Most developed stage of breasts)
involution and senile atrophy.
Atrophy of breast (observations)
with ageing, the breast tissue begins to atrophy so there are more fat tissue than breast -> appear more translucent rather than whitish
Major reason for pathology in breasts
The sensitivity for ovarian hormones, hormones of pregnancy and other growth factors in the female breast predispose this organ to a number of pathological conditions.
Clinical presentations of breast diseases
- pain,
- presence of a dominant lump, or
- abnormal nipple discharge.
epidemiology of breasts diseases
40% - Fibrocystic changes
30% - No disease
13% - Miscellaneous benign conditions
10% - Breast cancer
7% - Fibroadenoma
Why are benign breast conditions of interest
because they may mimic breast cancer - e.g. nipple discharge, breast lump
Benign breast conditions by categories
1) INFLAMMATORY LESIONS
- Acute mastitis & breast abscess
- Mammary duct ectasia
- Fat necrosis
- Granulomatous mastitis
2) FIBROCYSTIC DISEASES
- Cystic formation & fibrosis
- Apocrine metaplasia
- Epithelial hyperplasia
3) PROLIFERATIVE LESIONS
- Hyperplasia (ductal hyperplasia; lobular hyperplasia)
- Sclerosing adenosis
- Radial scars (complex sclerosing lesions)
4) BENIGN TUMORS
- Duct/intraduct papilloma
- Fibroadenoma
Types of breast Inflammatory lesions
- Acute mastitis & breast abscess
- Mammary duct ectasia
- Fat necrosis
- Granulomatous mastitis
Acute mastitis & breast abscess characteristics
- uncommon except during lactation
- may be the result of infection (bacterial entry) via the nipple due to abrasion or crack, acquired from the mouth of the baby during breastfeeding
- four cardinal signs of inflammation (red, swollen, heat, pain)
- **important to differentiate from inflammatory breast cancer (an advance stage of malignancy)
- Benign inflammatory lesion
Mammary duct ectasia characterisitcs
- uncertain aetiology
- presents clinically as dilated ducts filled with cheesy material in the area adjacent to the aerola
- Ulceration and dilation of the ducts allows liberation of lipids into the connective tissue stroma that leads to a chronic granulomatous inflammatory reaction.
- Fibrosis can lead to nipple retraction and clinically mimic carcinoma
- Benign inflammatory lesion
Mammary duct ectasia, because:
1) chessy material is observed filling the mammary duct
leakage of cheesy material into connective tissue - classical histological feature of mammary duct ectasia
Fat Necrosis characteristics
- Most commonly seen in women with obese, pendulous breasts
- due to trauma.
- There is a localised firm or even hard mass which can on occasions be adherent to the skin and thus be easily mistaken for carcinoma
- Traumatic rupture of fat cells results in a foreign-body granulomatous reaction and subsequent fibrosis and retraction
- Benign inflammatory lesion
Other Granulomatous Lesions
- florid foreign body type granulomatous reaction
- Breast tuberculosis
- Idiopathic granulomatous mastitis
florid foreign body type granulomatous reaction (e.g. Paraffinoma)
- In the past foreign material such as paraffin wax (Paraffinoma) or silicone fluid were injected as means of increasing breast size (breast augmentation)
- These could give rise to florid foreign body type granulomatous reaction.
- Leading to fibrosis and cyst formation
- holes here are filled with paraffin, much fibrosis, may be palpated as mass (empty round spaces due to lipids being dissolved by multinucleated giant cells)
- benign breast inflammatory lesion, granulomatous in nature
Paraffinoma
- florid foreign body type granulomatous reaction.
- used to occur when women wanted to augment their breasts -> inject paraffin (inert)
- [fig. 1] holes here are filled with paraffin, much fibrosis, may be palpated as mass
- [fig. 2] empty round spaces due to lipids being dissolved multinucleated giant cells
Breast tuberculosis
- An uncommon complication of pulmonary tuberculosis caused by mycobacterium tuberculosis;
- benign breast inflammatory lesion, granulomatous in nature
Idiopathic granulomatous mastitis
- benign breast inflammatory lesion, granulomatous in nature
- may have an autoimmune base.
Breast fibrocystic disease (cause, epidemiology, types, presentations)
- Cause: Cyclical hormonal influences do not affect all parts of the breast equally in each cycle. Hormonal imbalances such as excess of oestrogens, a deficiency of progestrone as well as abnormal end- organ metabolism of hormones are all thought to contribute to the pathogenesis of this multi- patterned disease.
- Epidemiology: Most common around 30 years of age (younger females), it is rare after the menopause.
- Types: cystic formation & fibrosis; apocrine metaplasia; epithelial hyperplasia
- Presentation:
i) Accumulation of liquids in mammary ducts, thus forming cysts
ii) May present in come-and-go manner: after menstruation, estrogen start accumulating -> just before mens. high estrogen, so high water retention -> cysts are filled with fluid and woman may detect a palpable lump which may disappear after mens due to lowered estrogen -> come-and-go
iii) tends to be generalised but frequently a localised area draws attention to the disease.
iv) The breast tissue is firmer and more nodular than usual - but not hard and fixed to surrounding tissues as in carcinoma.
v) Pain present due to breasts bring streched
vi) Cysts 2-10 mm in diameter may be seen and they frequently occur in clusters. Large cysts occur.
[Fig 1]
- whitish areas due to stromal fibrosis
- black, smooth in outline,well-circumscribed
- congested areas are due to increased vascularity or fluid
[Figure 2]
Labelling
Apocrine metaplasia
- the ductal epithelium changes to pink cells with budding of the luminal aspect.
- abundance of eosinophilic/pinkish cytoplasm and enlarged and prominent nucleoli of apocrine cells observed (see fig.)
Fibrocytic disease - Apocrine metaplasia
- abundant eosinophilic/pinkish cytoplasm
- apocrine cells have prominent nucleoli
Epithelial hyperplasia
- proliferation of ductal lining epithelium
- the more severe and atypical the degree of hyperplasia, the greater degree it can be associated with increased chance of malignancy
- haphazard proliferation -> when they form sieve like, well organized spaces; more likely ductal carcinoma in situ
Hyperplasia
- may involve the ducts (ductal hyperplasia) or the lobules (lobular hyperplasia)
- Ductal hyperplasia -> Number and size of ducts increase
- Lobular hyperplasia -> acini increased in number making the whole terminal lobule enlarged
Sclerosing adenosis
- Adenosis refers to enlargement of breast lobules. If there are many enlarged lobules near one another, this collection may be large enough to be palpable.
- Sclerosing adenosis is a special type of adenosis in which the enlarged lobules are distorted by fibrous tissue and simulate malignancy.
- May be found during childbearing and peri-menopausal years.
Radial scars (complex sclerosing lesions)
- distortion of normal arrangement of breast tissue (ducts and acini) due to fibrosis
- some ducts are filled with fluid, therefore also fibrocystic
- usually only detected radiologically.
- Can mimic carcinoma both clinically and radiologically.
- stellar lesion (resembling tubular carcinoma)
Fibroadenoma (Composition, epidemiology, features)
Composition: It is composed of benign epithelium and made up of glandular breast tissue and stromal tissue
Epidemiology: It is the commonest cause of a palpable lump up to the age of 30; More common in the young but can occur in any age
Features:
- Clinically it is a well-circumscribed (smooth in outline), firm, painless and mobile (since not fixed to breast tissues) lump [Fig 1]
- Dubbed “breast mouse” as it is mobile when palpated
- Is a solid lesion so can differentiate against a cyst via ultrasound
- proliferation of connective tissue [Stromal overgrowth, see Fig 2] that may compress ducts into slit-like spaces [Fig. 2]
Labelling and Identification of Pathology
Fibroadenoma
- stroma compresses the ducts to make them slit-like
- stroma overgrowth surrounding the ducts
Intraductal papilloma (Definition, epidemiology, features)
Definition: Benign tumors that grow within the breast ducts.
Epidemiology: Occurs any age
Features:
- usually within 4 cm of the nipple
- commonest cause of a bloody nipple discharge (carcinoma being the next most common cause)
- Can be solitary or multiple
i) Solitary usually involve large ducts near nipple (Commonest cause of unilateral bloodly nipple discharge)
ii) Multiple usually involve smaller ducts (and is associated with slight increased risk of breast cancer) - Papilloma very fleshy, will cause duct dilation [Fig 1]
- Still two cell types lining acini -> hence benign [Fig 2]
Phylloides tumor (composition, epidemiology, prognosis, features, treatment)
Composition: Composed of glandular breast tissue and stromal tissue
Epidemiology: The peak age is 45 years.
Malignancy: Range of clinical behaviour variable - from benign to malignant (majority of phylloides tumours behave in a benign fashion, 3-12% metastasize)
Prognosis:
- Simple enucleation of the tumour will result in a high frequency of recurrence (Incomplete excision may lead to recurrence)
- subsequent recurrences may result in development of malignancies therefore follow-ups are essential
Features:
- Resembles a fibroadenoma, but distinguished by the presence of an “overgrowth” of connective tissue stromal components and a frond-like/leaf-like arrangement [Fig 1] of the fibroepithelial element.
- Features for distinguishing the malignant form are: (i) increased mitoses (ii) cellular atypia (large pleomorphic nuclei, hyperchromatism; Fig 2), (iii) invasive edge, (iv) stromal overgrowth.
Treatment: The usual treatment for the benign phyllodes tumour is wide excision and for the malignant ones is mastectomy.
Labelling and Identification of pathology
Mammography (Nature, Functions, Observations, Usage, Limitations)
Nature: X-ray
Functions:
1) aims at detecting impalpable cancers
2) also be used to further characterise palpable lesions and to check for bi-laterality
Observations:
1) White spots (i.e. calcium deposits - microcalcification) can be detected against black background -> an early stage of breast carcinoma in-situ [Fig 2, between “horns”]
Usage:
- baseline for follow up
- observe size and extent of lesion
- presence of DCIS (ductal carcinoma in situ)
- detection of multifocal disease
- other non palpable abnormalities
- opposite breast
Limitations:
1) 10-20% of carcinomas may still be undetectable by mammography
2) Not suitable for younger women as they have denser (with less adipose tissue) breast structures -> as a result background more whitish and microcalcification cannot be readily detected due to lack of contrast
3) Lower sensitivity, therefore not a good universal screening method
Other modes of radiological detection of breast cancer
1) Ultrasonography (not good for screening but good for further grading the lesion or differen solid and cyst, Fig 1)
2) MRI
FNAC Diagnostic categories
- C1 Inadequate
- C2 Benign
- C3 Atypia
- C4 Suspicious of malignancy
- C5 Malignant
Inflammatory breast cancer
- Usually there is no single lump or tumor but presents with skin of breast appearing inflamed
- red, warm, peau d’orange appearance of skin due to blockage of lymph vessels in the skin by cancer cells (tumour emboli in lymphatics triggering an inflmmatory reaction)
- Poorer prognosis than typical invasive cancers, with higher chance of metastatic spread
- inflammation mimics signs of acute mastitis (swollen, hot, painful)
Paget’s disease of the nipple
- Usually presents with erosion of the nipple and areola, which are red and weeping but occasionally dry, scaly and psoriatic [Fig 1]
- There is always an underlying intraductal or invasive carcinoma
- It is characterized microscopically by the invasion of the epidermis by Paget’s cells, which are large, round to oval with pale cytoplasm and contain mucin [Fig 2]
