B8-035 Breast Histology & Physiology Flashcards
[hormone] stimulates the development of the lactiferous ducts
estrogen
(with prolactin)
[hormone] stimulates the development of the lobules
progesterone
only with […] does the breast fully mature
pregnancy
milk production in pregnancy is inhibited by [hormone]
progesterone
rising levels of [hormone] throughout pregnancy increases prolactin secretion
estrogen
suckling of the infant causes the release of [hormone], causing milk ejection by contraction of the myoepithelial cells
oxytocin
surrounds the glands and ducts with connective and adipose tissue
Interlobular mammary stroma
Basic histopathological units of the mammary gland
Terminal ductal lobular units (TDLU)
loose, cell-rich connective tissue within the TDLU
Intralobular stroma
Outer layer of the TDLU is comprised of […] cells that are contractile and route the milk to the ducts in lactating breasts
myoepithelial
the Inner layer of the TDLU is comprised of cubic, apocrine glandular […] epithelial cells that can produce milk
luminal
distinct histological features of a lactating breast
very large lobules with tubulo-alveolar ends
small amounts of interlobular connective tissue
what changes to the breast are occurring in the proliferative phase of the menstrual cycle?
no changes
what changes to the breast are occurring in the secretory phase of the menstrual cycle?
↑ estrogen and ↑ progesterone → cell proliferation, ↑ number of acini, edema of interlobular stroma
what changes to the breast are occurring during menstruation?
desquamation and regression
what changes in the breast occur due to age? [4]
involution of the breasts due to a decrease in estrogen levels
Atrophy of mammary glands and connective tissue stroma
The milk duct system is preserved.
Relative increase in fat percentage due to replacement of stroma with fat
main mammographic signs of breast carcinoma [2]
densities
calcifications
most common causative agent of mastitis
S. aureus
squamous metaplasia of lactiferous ducts (SMOLD) has a strong association with […]
smoking
painful, erythematous subareolar mass
may be interpreted clinically as an abscess
squamous metaplasia of lactiferous ducts (SMOLD)
epithelium extends into ducts, keratin accumulates and ruptures causing inflammatory response
squamous metaplasia of lactiferous ducts (SMOLD)
post-menopausal women with unilateral nipple pain/bleeding
dilated ducts with lipid secretions and foamy histiocytes on microscopy
mammary duct ectasia
early lesions have hemorrhage and indurated fat
later, necrotic fat cells surrounded by lipid filled macrophages and neutrophils
fat necrosis
(commonly associated with trauma)
fibrocystic change has […] risk of developing into breast cancer
low
3 principle morphologic changes of fibrocystic change
- cystic change/apocrine metaplasia: lobules dilate or join into larger cysts
- fibrosis from cyst rupture
- adenosis: increase in number of acini per lobule
blue dome cyst
fibrocystic change
benign epithelial proliferation of duct
slit-like fenestrations on sides of duct
usual ductal hyperplasia
(low risk of developing invasive breast cancer)
acini and stomal fibrosis with microcalcifications
sclerosing adenosis
(low risk of developing invasive breast cancer)
benign lesion with fibroelastosis and entrapped glandular structures
may mimic invasive carcinoma on imaging due to stellate appearance
radial scar/complex sclerosing lesion
(associated with intraductal hyperplasia)
small fibroepithelial tumor within lactiferous ducts, typically beneath areola
most common cause of nipple discharge
intraductal papilloma
(2-3x risk of invasive breast carcinoma)
very very similar to low grade DCIS, but small amount and not well developed
atypical ductal hyperplasia
(close follow up due to increased risk of invasive cancer)
non-invasive neoplastic proliferation of small, dyscohesive cells expanding less than 50% of the TDLU
atypical lobular hyperplasia (ALH)
(4-5x risk of invasive breast cancer)
[…] make milk that drains via ducts to the nipple
lobules
The […] is the functional unit of the breast
terminal duct lobular unit
Lobules and ducts are lined by […] layers of epithelium
two
luminal cell layer and myoepithelium
inner cell layer lining the ducts and lobules; responsible for
milk production in the lobules
luminal cell layer
outer cell layer lining ducts and lobules; contractile
function propels milk towards the nipple.
myoepithelial cell layer
During pregnancy, breast lobules undergo […]
hyperplasia
after menopause, breast tissue undergoes […]
atrophy
Inflammation of the subareolar ducts
Usually seen in smokers
Clinically presents as a subareolar mass with nipple retraction
periductal mastitis
Inflammation with dilation of the subareolar ducts
classically arises in multiparous postmenopausal women
mammary duct ectasia
Presents as a periareolar mass with green-brown nipple discharge
Chronic inflammation with plasma cells is seen on biopsy
mammary duct ectasia
Papillary growth, usually into a large duct
intraductal papilloma
Characterized by fibrovascular projections lined by epithelial (luminal) and myoepithelial cells
intraductal papilloma
Classically presents as bloody nipple discharge in a premenopausal woman
Must be distinguished from papillary carcinoma, which also presents as bloody nipple discharge
intraductal papilloma
characterized by fibrovascular projections lined by luminal epithelial cells without underlying myoepithelial cells.
papillary carcinoma
Fibroadenoma-like tumor with overgrowth of the fibrous component; characteristic ‘leaf-like’ projections are seen on biopsy
phyllodes tumor
(can sometimes be malignant)
during pregnancy, milk production is inhibited my high levels of […]
progesterone
[…] causes ejaculation of milk through myoepithelial cells
oxytocin
do breast TDLUs remain the same throughout the menstrual cycle?
no, fluctuate with ovulation
male and female breast histology are [same/different] pre-puberty
same
how do breast TDLUs change after cessation of lactation?
regress
the most common etiology for nipple discharge is
solitary large duct papilloma
bloody or serous nipples discharges are more commonly associated with [benign/malignant] lesions
benign
milky nipple discharge [is/is not] associated with malignancy
is not
the risk of malignancy with nipple discharge increases with […]
age
usual ductal hyperplasia carries a 1-2% risk of developing malignancy in [one/both] breasts
both
(follow up with routine mammogram)
management of usual ductal hyperplasia
follow up with routine mammograms
poorly defined periareolar mass with thick, cheesy nipple secretion
duct ectasia
dilated duct with multiple branching fibrovascular cores lined by luminal and myoepithelial cells
intraductal papilloma
“lumpy bumpy” breast with microcalcifications, cysts, apocrine metaplasia, and fibrosis
fibrocystic changes
unilateral, erythematous, painful breast mass
biopsy shows neutrophils
acute mastitis
