Breast
The breast has 2 main components:
- Glandular tissue:
o ducts: open into the nipple
o lobules: secreting component, made of acini – each lobe drains into a
major lactiferous duct that dilates into a lactiferous duct sinus beneath the
areola opening into the nipple.
- Stromal tissue: space between lobes, both interlobular and intralobular.
Composed of complex mixture of fibroblasts, blood vessels, lymphatics,
inflammatory cells, ECM:
The superficial portions are lined by
keratinizing squamous cells that
abruptly change in the rest of the duct
and lobular system to a double-
layered epithelium, composed of
inner luminal and outer
myoepithelial cells.
Each terminal duct lobular unit
(organoid structure) is composed of
branched tubulo-alveolar glands
organized into lobes with the function
of feeding the newborn. Myoepithelial
cells provide structural support to the
lobules and assist in milk ejection
during lactation whilst lobular luminal
epithelial cells produce milk.
The breast structure undergoes marked periodic changes during the reproductive years:
- during each menstrual cycle under the influence of estrogen and progesterone,
cell proliferation increases leading to an increased number of acini per lobule and
an edematous intralobular stroma
- during pregnancy and breastfeeding: lobules increase progressively in number
and size, until the breast becomes composed almost entirely of lobules
separated by relatively scant stroma. When lactation stops, epithelial cells
undergo apoptosis and lobules partially regress.
- involution of the lobules and stroma: after age 30 and after menopause, radio-
opaque fibrous stroma converts into radiolucent adipose tissue.
Clinical presentation of breast diseases
The most common symptoms reported by women with breast disorders are:
- Pain (mastalgia or mastodynia): usually indicative of benign disease but about
10% of breast cancers present with pain
o cyclic with menses
, o non-cyclic: localized to one area of the breast usually due to ruptured
cysts, physical injury, and infection. No specific lesion is identified
- Palpable masses: must be distinguished from normal nodularity or ‘lumpiness’
of the breast
- Nipple discharge: less common, more worrisome for malignancy when
spontaneous or unilateral. Galactorrhea is not associated with malignancy.
Bloody or serous discharge is usually due to large duct papillomas and cysts.
Palpation of the breast allows the detection of about 1/3 of breast cancers however
routine breast examination has not led to a significant reduction in mortality because
most invasive cancers have metastasized before they reach a palpable dimension of 2-
3cm. This is why mammographic screening was introduced; it allows visualization of:
- Densities: rounded densities are usually the manifestations of fibroadenomas
whilst irregular densities are usually malignant
- Calcifications: usually associated with benign lesions however when irregular,
numerous and clustered they are frequently associated with malignancy.
Nonetheless, mammography does not allow visualization of 10% of invasive cancers,
which are frequently the most aggressive, because:
- they occur in younger individuals so the presence of radiodense tissue
surrounding the lesion makes it undetectable → US (or MRI) is used in young
women and it is more useful in distinguishing solid from cystic masses, and in
better defining the borders of the mass.
- cancers may be located in the periphery and hence breast
not be nodule
included&inprevalence
the scan
- the tumor may grow in a diffuse pattern with no desmoplastic response.
Breast nodules
A breast nodule is a very common finding in women:
- in 30% of cases it is insignificant, only related to
hormonal changes of the breast parenchyma
- in 40% of cases it is due to fibrocystic changes
- in 20% cases it is related to a benign nodule
- in 10% cases it is a malignant nodule.
Upon finding a breast nodule, evaluate of the following:
- age: a nodule in a 20 year old is benign in 99% of cases
- consistency: malignant lesions are hard, since they are rich in fibrous
collagenous stroma
- mobility: malignant cancers tend to be fixed to surrounding tissue in the deepest
layers of the breast
- location: a nodule near the nipple, until the segmental ducts is usually a benign
papilloma, whilst lesions deep in the parenchyma are usually fibroadenomas or
cancer.
The breast has 2 main components:
- Glandular tissue:
o ducts: open into the nipple
o lobules: secreting component, made of acini – each lobe drains into a
major lactiferous duct that dilates into a lactiferous duct sinus beneath the
areola opening into the nipple.
- Stromal tissue: space between lobes, both interlobular and intralobular.
Composed of complex mixture of fibroblasts, blood vessels, lymphatics,
inflammatory cells, ECM:
The superficial portions are lined by
keratinizing squamous cells that
abruptly change in the rest of the duct
and lobular system to a double-
layered epithelium, composed of
inner luminal and outer
myoepithelial cells.
Each terminal duct lobular unit
(organoid structure) is composed of
branched tubulo-alveolar glands
organized into lobes with the function
of feeding the newborn. Myoepithelial
cells provide structural support to the
lobules and assist in milk ejection
during lactation whilst lobular luminal
epithelial cells produce milk.
The breast structure undergoes marked periodic changes during the reproductive years:
- during each menstrual cycle under the influence of estrogen and progesterone,
cell proliferation increases leading to an increased number of acini per lobule and
an edematous intralobular stroma
- during pregnancy and breastfeeding: lobules increase progressively in number
and size, until the breast becomes composed almost entirely of lobules
separated by relatively scant stroma. When lactation stops, epithelial cells
undergo apoptosis and lobules partially regress.
- involution of the lobules and stroma: after age 30 and after menopause, radio-
opaque fibrous stroma converts into radiolucent adipose tissue.
Clinical presentation of breast diseases
The most common symptoms reported by women with breast disorders are:
- Pain (mastalgia or mastodynia): usually indicative of benign disease but about
10% of breast cancers present with pain
o cyclic with menses
, o non-cyclic: localized to one area of the breast usually due to ruptured
cysts, physical injury, and infection. No specific lesion is identified
- Palpable masses: must be distinguished from normal nodularity or ‘lumpiness’
of the breast
- Nipple discharge: less common, more worrisome for malignancy when
spontaneous or unilateral. Galactorrhea is not associated with malignancy.
Bloody or serous discharge is usually due to large duct papillomas and cysts.
Palpation of the breast allows the detection of about 1/3 of breast cancers however
routine breast examination has not led to a significant reduction in mortality because
most invasive cancers have metastasized before they reach a palpable dimension of 2-
3cm. This is why mammographic screening was introduced; it allows visualization of:
- Densities: rounded densities are usually the manifestations of fibroadenomas
whilst irregular densities are usually malignant
- Calcifications: usually associated with benign lesions however when irregular,
numerous and clustered they are frequently associated with malignancy.
Nonetheless, mammography does not allow visualization of 10% of invasive cancers,
which are frequently the most aggressive, because:
- they occur in younger individuals so the presence of radiodense tissue
surrounding the lesion makes it undetectable → US (or MRI) is used in young
women and it is more useful in distinguishing solid from cystic masses, and in
better defining the borders of the mass.
- cancers may be located in the periphery and hence breast
not be nodule
included&inprevalence
the scan
- the tumor may grow in a diffuse pattern with no desmoplastic response.
Breast nodules
A breast nodule is a very common finding in women:
- in 30% of cases it is insignificant, only related to
hormonal changes of the breast parenchyma
- in 40% of cases it is due to fibrocystic changes
- in 20% cases it is related to a benign nodule
- in 10% cases it is a malignant nodule.
Upon finding a breast nodule, evaluate of the following:
- age: a nodule in a 20 year old is benign in 99% of cases
- consistency: malignant lesions are hard, since they are rich in fibrous
collagenous stroma
- mobility: malignant cancers tend to be fixed to surrounding tissue in the deepest
layers of the breast
- location: a nodule near the nipple, until the segmental ducts is usually a benign
papilloma, whilst lesions deep in the parenchyma are usually fibroadenomas or
cancer.
