Mammo Flashcards
Anatomy
nipple
The nipple is a circular smooth muscle that overlies the 4lh intercostal space. There
are typically 5-10 ductal openings. Inversion is when the nipple invaginates into the breast.
Retraction is when the nipple is pulled back slightly. They can both be normal if chronic. If
they are new, it should make you think about underlying cancers causing distortion. The
nipple is supposed to be in profile so you do n ’t call it a mass. The areola will darken
normally with puberty and parity. Nipple enhancement on contrast enhanced breast MRI is
n o rm a l, don ’t call it Pagets!
Anatomy
fibroglandular tissue
The breast mound is fibrous
tissue with fat, ducts, and glands laying on top o f the
anterior chest wall. The axillary extension is called the
“to// o f Spence.” The upper outer quadrant is more
densely populated with fibroglandular tissue, which is
why most breast cancers start there. There is usually no
dense tissue in the medial/ inferior breast and
retroglandular regions. These are considered “danger
zones” and are often where the cancer hides.
Anatomy
danger zones
where there is
usually no dense fibroglandular
tissue
Anatomy
coopers ligaments
These are thin sheets o f fascia
that hold the breasts up. They are the tiny white lines on mammography and the echogenic
lines on US. Straightening and tethering o f the ligaments manifests as “architectural
distortion” which occurs in the setting o f surgical scars, radial scars, and IDC.
Anatomy
breast asymmetry
This is common and normal (usually), as long as there are no other
findings (lumps, bumps, skin thickening, etc..). For multiple choice, an asymmetric breast
should make you think about the “shrinking breast ” o f invasive lobular breast cancer. I f the
size difference is new or the parenchyma looks asymmetrically dense, think cancer.
Anatomy
lobules
The lobules are the flower shaped milk makers o f the breast. The terminal duct
and lobule are referred to as a “terminal duct lobular unit” or TDLU. This is where most breast cancers start.
Anatomy
ducts
The ductal system branches like the roots or branches o f a tree. The branches overlap wide areas and are not cleanly segmented like slices o f pie. The calcifications that appear to follow ducts (“ linear or segmental”) are the ones where you should worry about cancer.
Anatomy
lactiferous sinus
Milk from the lobules drains into the major duct under the nipple. The
dilated portion o f the major duct is sometimes called the lactiferous sinus. This thing is normal (not a mass).
Anatomy
blood supply/lymphatic drainage
The majority (60%) o f blood flow to the breast is via the internal mammary. The rest is via the lateral thoracic and intercostal perforators. Nearly all (97%) o f lymph drains to the axilla. The remaining 3% goes to the internal mammary nodes.
Anatomy
axillary node levels
The axilla is sub-divided into three separate levels using the
pectoralis minor muscle as a landmark. Supposedly drainage progresses in a step wise
fashion - from level 1 -> level 2 -> level 3 and finally into the thorax.
Anatomy
rotter nodes
These are the nodes between the pec minor and major. They have a fancy
name which usually makes them high yield. However, Rotter was German and test writers
tend to prefer French sounding trivia. The only exception to this is Nazis. German sounding
medical vocab words named after Nazis are fair game. To save you the trouble o f looking it
up - Rotter died before Hitler took power so he wasn’t a Nazi (probably). Since they
probably aren’t gonna ask the vocab word, the only other conceivable piece o f trivia I can
imagine being asked would be that these are at the same level as level 2.
Anatomy
axillary nodes quick
Level 1: Lateral to Pec Minor
Level 2: Deep to the Pec Minor
Level 3: Medial and Above Pec Minor
Rotter Node: Between the Pec Minor and Major
Anatomy
Metastasis to the Internal Mammary Nodes
If you can see them on ultrasound they are abnormal. Isolated mets to these nodes is not a common situation (maybe 3%). When you do see it happen, it’s from a medial cancer. More commonly, mets in this location occur after
disease has already spread into the axilla (in other words - it’s spreading everywhere).
Anatomy
sternalis muscles
This is an Aunt Minnie. It’s a non-functional muscle next to the sternum
that can simulate a mass. About 5% o f people have one and it’s usually unilateral.
Anatomy
sternalis muscle testable trivia
- WTF is that ?- Recognize the Aunt Minnie, and d o n ’t get tricked into doing a biopsy on it, e tc …
- How You See It? It is ONLY SEEN ON THE CC VIEW.
Handling this in real life is all about the old gold. Find that thing on the priors (even better is a C T ) , CC only, never on the MLO.
Breast Development
overview
The “milk strea k ’’ is the embryologic buzzword to explain the location o f the normal breast
and location o f ectopic breast tissue. Just know that the most common location for ectopic
breast tissue is in the axilla (second most common is the inframammary fold). Extra
nipples are most commonly in the same locations (but can be anywhere along the “milk
streak”). At birth, both males and females can have breast enlargement and produce milk
(maternal hormones). As girls enter puberty, their ducts elongate and branch (estrogen
effects), then their lobules proliferate (progesterone effects). I f you biopsy a breast bud
(why would you do that?) you could damage it and potentially fuck up breast
development…. and then get sued.
Breast Development
Follicular Phase (day 7-14):
Estrogen Dominates. Best time to have both mammogram and MRI.
Breast Development
Luteal Phase (day 15-30):
Progesterone Dominates. This is when you get some breast tenderness (max at day 28-30). Breast density increases slightly.
Breast Development
Pregnancy:
Tubes and Duct Proliferate. The breast gets a lot denser (more
hypoechoic on US), and ultrasound may be your best bet if you have a mass.
Breast Development
Perimenopausal
Shortening o f the follicular phase means the breast gets more
progesterone exposure. More progesterone exposure means more breast pain, more
fibrocystic change, more breast cyst formation.
Breast Development
Menopause (“The Floppy S ta ge”):
Lobules go down. Ducts stay but may become
ectatic. Fibroadenomas will degenerate (they like estrogen), and get their “popcorn”
calcifications. Secretory calcifications will develop (*but not for 15-20 years post
menopause) .
Breast Development
Hormone Replacement Therapy
Breasts get more dense (especially estrogenprogesterone
combos). Breast pain can occur, typically peaking in the first year.
Fibroadenoma (who like to drink estrogen) can grow.
High Yield Trivia Regarding Breast Anatomy / Physiology
The nipple can enhance with contrast on MRI. This is normal (not Pagets).
Most cancers occur in the upper outer quadrant.
Most cancers start in the terminal duct lobular unit (TDLU).
Majority (60%) o f blood flow is via the internal mammary.
Mets to the Internal Mammary Nodes are uncommon (3%) - seen in medial cancers.
Axillary Node Levels (1, 2, 3 - lateral to medial)
Stemalis is usually unilateral, and only on the CC, NEVER on MLO.
Breast Tenderness is max around day 27-30.
Mammography and MRI are best performed in the follicular phase (days 7-14).
Don’t Biopsy a prepubescent breast - you can affect breast development
Perimenopause (5 0 ’s) is the peak time for breast pain, cyst formation
Fibroadenomas will degenerate (buzzword popcorn calcification) in menopause
Secretory Calcifications (buzzword “ rod-like) will develop 10-20 years post menopause
Lactation
density
As mentioned above, the breast gets a lot denser in the 3rd trimester.
Mammograms might be worthless, and ultrasound could be your only hope. In other
words, ultrasound has greater sensitivity than mammo in lactating patients.