B8.035 The Breast

Question 1

basic anatomy of the normal breast

Answer 1

6-10 major ductal systems originate at the nipple

successive branching of the large ducts eventually leads to the terminal duct lobular unit (TDLU)

Question 2

TDLU histology

Answer 2

functional secretory unit
ducts and lobules are lined by an inner ductal epithelium and an outer myoepithelial layer
basal lamina of type 4 collagen and laminin is present outside of the myoepithelial cell layer and serves to demarcate the breast TDLU from the surrounding stroma

Question 3

interlobular stroma

Answer 3

dense fibroconnective tissue admixed with adipose tissue

Question 4

intralobular stroma

Answer 4

closely surrounds TDLU
loose, delicate, myxomatous stroma
hormonally responsive
contains scattered lymphocytes

Question 5

prepubertal breast in both males and females

Answer 5

large duct system ends in terminal ducts with minimal lobule formation

Question 6

male breast development

Answer 6

T induces the involution of the duct system

no TDLUs develop

Question 7

normal female breast at menarche

Answer 7

terminal ducts five rise to lobules
interlobular stroma increases in volume
E stimulates the development of ducts (in the presence of prolactin)
P stimulates the formation of lobules

Question 8

normal breast during follicular phase

Answer 8

lobules quiescent

Question 9

normal breast after ovulation

Answer 9

changes due to combined effect of E and P

• # of acini per lobule increases
• vacuolization of epithelial cells
• marked intralobular stromal edema

Question 10

what happens to the normal breast during pregnancy

Answer 10

becomes completely mature and functional
lobules increase both in number and size
true secretory glands form in the lobule
secretory vacuoles of lipid material appear

Question 11

what influences the changes that occur in the breast during pregnancy

Answer 11

E. P, prolactin, and placental lactogen

Question 12

process of milk production

Answer 12

rising levels of E throughout pregnancy increase prolactin secretion
prolactin stimulates milk production
milk production is inhibited by high levels of P during pregnancy

Question 13

lactation process

Answer 13

occurs after birth

• removal of the P inhibition on prolactin effect
• suckling > release of oxytocin > milk ejection by contraction of myoepithelial cells

Question 14

colostrum

Answer 14

immediately after delivery

high in protein

Question 15

what changes occur in milk

Answer 15

becomes higher in fat and calories within the first 10 days

Question 16

where are prolactin receptors

Answer 16

on inner epithelial cells

Question 17

where are oxytocin receptors

Answer 17

on outer myoepithelial cells

Question 18

secretory products from mammary alveolar cells

Answer 18

fat
dimeric IgA
protein
lactose

Question 19

dimeric IgA in breast milk

Answer 19

produced by plasma cells, transported into the lumen by transcytosis and released into the milk to provide passive immunity to the nursing baby

Question 20

what does breast milk provide to an infant

Answer 20

complete nourishment

protection against infection and allergies

Question 21

what happens in the normal breast after cessation of lactation

Answer 21

lobules regress and atrophy

Question 22

postmenopausal breast changes

Answer 22

atrophy of ducts and lobules
shrinkage of intralobular and interlobular stroma
radio-dense fibrous interlobular stroma is progressively replaced by radiolucent adipose tissue
lobular acini and stroma may almost totally disappear

Question 23

presentations of breast disease

Answer 23

pain
palpable masses
lumpiness
nipple discharge

Question 24

source of pain in breasts

Answer 24

ruptured cysts
prior injury
infection
no lesion

Question 25

nipple discharge

Answer 25

bloody or serous are most commonly associated with benign lesions
most common etiology is intraductal papilloma
milky nipple discharge not associated with malignancy
most worrisome when spontaneous and unilateral

Question 26

sens and spec of mammography

Answer 26

increased with age as intralobular stroma is less dense