Session 11 - The breast Flashcards
What does each lobule of the breast contain?
Alveoli, blood vessels and lactiferous ducts
What is responsible for milk let down?
myoepithelial cells
How much colostrum is secreted per day in the first week?
40 ml/day
What is the purpose of collustrum?
Provides protein, and immunoglobins for passive immunity
How long is mature milk produced post birth?
As long as the baby suckles
Name the 2 proteins found in mature milk
lactoglobulin and lactalbumin
Where does the synthesis of milk take place?
in the alveolar cells
Describe how breast tissue develops from bith to pregnancy
Birth - few lactiferous ducts only
Puberty - more oestrogen = more ducts and forming of alveoli
Pregnancy - high progesterone:oestrogen ratio develops alveoli more, hypertrophy of ductular-lobular-alveolar system and prominent lobules form. Alveolar cells differentiate to be able to produce milk in mid gestation.
What is the purpose of suckling?
Initiates and maintains secretion by a neuro-endocrine reflex by mechanically stimulating receptors in nipple.
What happens at birth to levels of hormones? What hormone does the breast become responsive to?
Oestrogen and progesterone fall
Breast becomes responsive to prolactin
Describe how suckling promotes release of milk
Mechanical stimulation results in impulses travelling to hypothalamus and reducing secretion of dopamine and vaso-active intestinal peptide, promoting prolactin secretion.
Describe the hormonal control of milk let down. How does this hormone release milk and what other important function does it have?
Let down caused by increase in secretion of oxytocin.
Oxytocin contracts myoepithelial cells surrounding alveoli, ejecting milk. Also keeps uterus clamped down on open placenta blood vessels
How does cessation of lactation occur?
If suckling stops, prolactin levels decrease. Also milk in breast builds up and causes turgor induced damage to ducts.
What happens to breast tissue as women get older? why is this good for mammograms?
Interlobular stroma replaced by adipose tissue. Mammograms easier to interpret
Where can 3rd nipples occur?
Along the milk line
What characteristics of pain in the breast suggest pathology? What could it be?
Non-cyclical and focal. Could be ruptured cysts, injury or inflammation
What are worrying features of a palpable mass? Would could it be?
If hard, craggy, and fixed. COuld be invasive carcinomas, fibroadenomas, cysts
When is nipple discharge concerning? What could it be?
If occurs spontaneously and unilateral
Could be pituitary adenoma or side effect of OCP
During what ages and when are women invited for breast screening?
50-70 every 3 years
What age do fibroadenomas occur most often>
<30
what age do phyllodes tumours most likely occur?
60s
What age does breast cancer most likely occur?
rare before 25, inidence increases with age.
77% occurs in women >50
What organism causes acute mastitis?
Staphylococcus aureus
What is acute mastitis? How is it treated?
Occurs during lactation due to nipple cracks and fissures. painful breast and often fevers. May be breast abscesses.
Treated by expressing milk and antibiotics.
What is duct ectasia?
dilation and inflammation of lactiferous duct. May have peri-areolar mass and/or nipple discharge
What can gynaecomastia indicate?
hormonal abormalities, cirrhosis of liver (oestrogen not broken down), fat people (adipocytes convert androgens to oestrogen), testicular tumour, drug use.
Describe the histology of a fibrocystic change in the breast
cyst formation, fibrosis, apocrine metaplasia
What is epithelial hyperplasia?
Epithelial cells get bigger and fill and distend ducts and lobules
How might a papilloma of the breast present?
nipple discharge (may be bloody), or small palpable mass
Describe the histology of a papilloma
Intraduct lesion consisting of multiple branching fibrovascular cores covered by myoepithelial and epithelial cells
how would you identifty a fibroadenoma on inspection?
well defined boundaries, mobile mass
What are phyllodes tumours?
stromal tumours
How do phyllodes tumours present histologically?
nodules of proliferating stroma covered by epithelium. Stroma is more cellular and atypical than in fibroadenomas
Is phyllodes tumours malignant or benign?
can be either
Why does long interval between menarche and menopause, or reproductive history increase risk of breast cancer?
longer exposure to oestrogen
How can you classify breast carcinomas?
in situ or invasive. Ductal or lobular.
What is an in situ carcinoma? Is it malignant?
Neoplasm limited to ducts and lobules by basement membrane
Cannot metastise.
What is an invasive carcinoma?
Carcinoma invaded beyond the basement membrane into the stroma.
If a breast cancer is palpable, what does that mean?
More than half of patients will have axillary lymph node metastases
Which lymph nodes are breast cancers most likely to spread to?
lymph nodes on ipsilateral axilla
What factors determine breast cancer prognosis?
in situ disease or invasive carcinoma
Histological subtype - invasive ductal carcinoma, no specific type has poorer prognosis
Tumour grade
Tumour stage - TMN
What is the triple approach to investigating and diagnosing breast cancer?
Clinical - history, exam, and genetics
Radiographic imaging - mammogram, USS
Pathology - Fine needle aspiration cytology and core biopsy
When is tamoxifen effective for breast cancers?
when there is a high amount of oestrogen receptors found on cancer
When is herceptin an effective treatment for cancers?
If there is a large amount of Her2 receptors found
What surgeries can benefit a breast cancer patient?
Mastectomy or breast conserving surgery
Axillary surgery if cancer has spread
