4. Breast p112-116 (Anatomy & Development)

Question 1

Nipple (normal) (7)

Answer 1

Circular smooth muscle overlying 4th intercostal space.
Typically 5-10 ductal openings.
Inversion: nipple invaginates into the breast.
Retraction: nipple pulled back slightly.
Can both be normal if chronic, if acute, think underlying cancer.
Areola will darken with puberty and parity.
Nipple enhancement on MRI is normal.

Question 2

Cooper ligaments (3)

Answer 2

Thin sheets of fascia holding the breasts up.
Tiny white lines on mammography, echogenic lines on US.
Straightening and tethering manifests as architectural distortion, occurs in surgical scars, radial scars and IDC.

Question 3

Fibroglandular tissue (5)

Answer 3

Breast mound is fibrous tissue with fat, ducts and glands laying on top of anterior chest wall.
Axillary extension is called “tail of spence”.
Upper outer quadrant is more densely populated with breast tissue, hence more cancers start there.
No dense tissue usually in medial/inferior breast and retroglandular regions.
These are considered danger zones, where cancer can hide.

Question 4

Breast asymmetry (3)

Answer 4

Common and usually normal, as long as no other findings.
Can be a sign of “Shrinking breast” in invasive lobular breast cancer.
Think cancer if size difference is new or parenchyma looks asymmetrically dense.

Question 5

Lobules (3)

Answer 5

Flower shaped milk producing areas. Terminal duct and lobule are referred to as a “terminal duct lobule unit” or TDLU.
Most breast cancers start here.

Question 6

Ducts (3)

Answer 6

Ductal system branches like roots or branches of a tree.
Branches overlap wide areas and not clearly segmented.
Calcifications that appear to follow the duct “linear or segmental” are most sus for cancer.

Question 7

Lactiferous sinus (3)

Answer 7

Milk from lobules drains into major duct under the nipple.
The dilated portion of the major duct is sometimes called Lactiferous Sinus.
It’s normal and not a mass.

Question 8

Blood supply/lymphatic drainage (3)

Answer 8

60% blood supply by internal mammary.
Rest is via lateral thoracic and intercostal perforators.
97% lymph drainage is to axilla, 3% to internal mammary nodes.

Question 9

Axillary lymph node levels (4)

Answer 9

Level 1: Lateral to pec minor
Level 2: under pec minor
Level 3: Medial to pec minor
Rotter node: Between pec major and minor

Question 10

Mets to internal mammary nodes (3)

Answer 10

If you can see the nodes on US, they’re abnormal.
Isolated mets to these nodes is uncommon, and if seen it’s usually from a medial cancer

Question 11

Sternalis muscle (3)

Answer 11

Non functional muscle next to sternum, can simulate a mass.
ONLY seen in CC view.
Usually unilateral.
Will be seen on previous imaging.

Question 12

Breast development/physiology (6)

Answer 12

“Milk streak” is the embryological buzzword to explain location of normal breast and location of ectopic breast tissue.
Most common location for ectopic breast tissue is the axilla (then inframammary fold).
Extra nipples are most commonly in the same locations, but can be anywhere along the “milk streak”.
Males and females can have breast enlargement at birth and produce milk (maternal hormones).
As girls enter puberty, ducts elongate and branch (due to oestrogen), then their lobules proliferate (progesterone).
Biopsying a breast bud can damage it and affect breast development.

Question 13

Follicular phase (breast) (3)

Answer 13

Day 7-14.
Oestrogen dominates.
Best time for mammogram and MRI.

Question 14

Luteal phase (breast) (4)

Answer 14

Day 15-30.
Progresterone dominates.
Some breast tenderness (max day 28-30).
Breast density increases slightly.

Question 15

Pregnancy (breast) (3)

Answer 15

Tubes and ducts proliferate.
Breast gets a lot denser (more hypoechoic on US).
US may be best bet if suspecting mass.

Question 16

Perimenipausal breast (3)

Answer 16

Shortening of follicular phase means breast gets more progesterone exposure, which means more breast pain, more fibrocystic change and more cyst formation.

Question 17

Menopausal (breast) (4)

Answer 17

Lobules decrease.
Ducts stay but become more ectatic.
Fibroadenomas degenerate (they like oestrogen) and get their popcorn calcifications.
Secretory calcifications will develop, but not for 15-20 years post menopause.

Question 18

Hormone replacement therapy (breast) (2)

Answer 18

Breast can get more dense (even more oestrogen-progesterone combos).
Breast pain can occur, peaking usually in first year.
Fibroadenomas can grow.

Question 19

Lactation (4)

Answer 19

Breast gets a lot denser in third trimester. Mammogram is more difficult and US becomes more useful.
Pituitary prolactinoma or meds (classically antipsychotics) can create similar bilateral increased density.
Biopsying a breast at this time risks creating a milk fistula. Need to stop breastfeeding to stop the fistula. The fistula can (rarely) get infected.

Question 20

Galactocele (3)

Answer 20

Benign fat containing lesion, typically seen on cessation of lactation.
Location is usually subareolar.
Appearance is varied, but can have classic fat-fluid level.

Question 21

Lactating adenoma (3)

Answer 21

Look like fibroadenomas, usually multiple.
Follow up 4-6 months post partum, post delivery or after cessation of lactation (ultrasound).
Rapidly regress after you stop lactation.