4. Breast p130-135 (Cancer)

Question 1

Invasive ductal carcinoma (4)

Answer 1

Most common invasive ductal carcinoma.
Ductal in origin but not confined to the duct (unlike DCIS).
Clinically: Hard, non-mobile, painless mass.
Imaging: irregular, high density mass with indistinct, spiculated margins and associated pleomorphic calcifications, and anti-parallel shadowing mass with echogenic halo on US.

Question 2

Invasive ductal NOS (4)

Answer 2

Most common breast cancer is undifferentiated and has no distinguishing histological features.
“Not Otherwise Specified”.
Make up 65% of invasive breast cancers.

Question 3

IDC subtypes (4)

Answer 3

Tubular
Mucinous
Medullary
Papillary

Question 4

Tubular IDC (4)

Answer 4

Small spiculated slow growing mass, favourable prognosis.
Often conspicuous on US.
Associated with radial scar.
Contralateral breast cancer 10-15%

Question 5

Mucinous IDC (2)

Answer 5

Round or lobulated, circumscribed mass.
Uncommon, better outcomes than IDC-NOS

Question 6

Medullary IDC (5)

Answer 6

Round or oval circumscribed mass without calcifications.
Axillary nodes can be large even in the absence of mets.
Typically younger patients (40s-50s).
Better outcome than IDC-NOS.
25% have BRCA 1 mutation.

Question 7

Papillary (4)

Answer 7

Complex cystic and solid.
Axillary nodes not common.
Typically elderly people, favours non-white people.
Second most common behind IDC-NOS

Question 8

Multifocal vs Multicentric breast cancer (3)

Answer 8

Multifocal: Multiple primaries in the same quadrant, classically same duct system.
- Less than 4-5cm from one another
Multicentric: Multiple primaries in different quadrants.
- Multiple discrete un-related sites.

Question 9

Synchronous bilateral breast cancer (2)

Answer 9

2-3% of women on mammography, with another 3-6% found on MRI.
Risk of bilateral disease is increased in infiltrating lobular types and multi-centric disease.

Question 10

DCIS (8)

Answer 10

Earliest form of breast cancer.
Cancer is confined to the duct.
Low, intermediate or high grade on histology.
Also split between comedo and non comedo on histology. Comedo is more aggressive.
3 potential appearances
- Suspicious calcifications (fine linear, branching or fine pleomorphic)
- Non-mass like enhancement on MRI
- Multiple intraductal masses on galactography.

Question 11

DCIS trivia (4)

Answer 11

10% of DCIS on imaging may have invasive component at time of biopsy.
25% of DCIS on core biopsy may have invasive component on surgical excision.
8% of DCIS will present as a mass without calcification.
Most common US appearance: Multilobulated mildly hypoechoic mass with ductal extension and normal acoustic transmission.

Question 12

Lobular (ILC) (4)

Answer 12

Second most common type of breast cancer after IDC-NOS.
Pathophysiology:
Cells lose e-cadherin, they no longer adhere to one another and infiltrate the breast like a spider web. This eventually causes architectural distorsion without a central mass, on CC view,
US: ill defined area of shadowing without a mass.

Question 13

“Shrinking breast” (3)

Answer 13

Buzzword for ILC. Breast isn’t actually smaller, just doesn’t compress as much.
Compared to normal breast, appears to be getting smaller.
May look the same size on physical exam.

Question 14

Dark Star (2)

Answer 14

Architectural distortion without a central mass.
DDx includes ILC, radial scar, surgical scar and IDC-NOS

Question 15

ILC vs IDC (3)

Answer 15

ILC is more often multifocal, less often mets to axilla, instead prefers to met to peritoneal surfaces.
ILC often has positive margins and more often treated with mastectomy.
Both have similar prognosis

Question 16

ILC trivia (8)

Answer 16

Tends to present later than IDC.
Usually older person.
Often only seen in CC view.
Calcification less common than ductal cancers.
Mammo buzzwords “dark star” and “shrinking breast”
US buzzword “shadowing without mass”
MRI: washout less common than IDC.
Axillary mets less common.
Prognosis similar to IDC (unless pleomorphic ILC, very aggressive).
More often multifocal and bilateral (1/3)

Question 17

Inflammatory breast cancer (4)

Answer 17

Poor prognosis.
Will usually get chemo before surgery, chance of positive margin is high.
Mastectomy is done for local control.
Swollen red breast similar to mastitis.
Skin thickening on mammogram (non specific).
Inflammation can improve with antibiotics but doesn’t resolve.
Dermal biopsy done if cannot fund underlying mass.

Question 18

Pagets (4)

Answer 18

Carcinoma in the nipple epidermis.
50% have palpable finding associated with skin changes.
Associated with high grade DCIS.
Wedge biopsy NOT to be done on any skin lesion affecting the nipple-areolar complex that doesn’t resolve with skin changes.
Pagets NOT considered T4, skin involvement doesn’t affect staging in this setting.

Question 19

High risk lesions (5)

Answer 19

These must come out after biopsy.
- Radial scar
- Atypical ductal hyperplasia
- Atypical lobulat hyperplasia
- LCIS
- Papilloma

Question 20

Radial scar (4)

Answer 20

Not actually a scar, but looks like one on histology.
Dense fibrosis around ducts, causing architectural distortion (dark scar).
High risk, needs excised.
Associated with DCIS or IDC (10-30%) and tubular carcinoma

Question 21

Atypical ductal hyperplasia (2)

Answer 21

DCIS but lacks quantitative definition by histology (>2 ducts involved).
Needs excision because it’s high risk and DCIS burden is often underestimated when this is present.

Question 22

LCIS (Lobular carcinoma in situ) (3)

Answer 22

Classically occult on mammogram.
Can be precursor to ILC. lower risk of malignancy than DCIS to IDC.
Pleomophic LCIS is worse than regular LCIS.

Question 23

Atypical lobular hyperplasia (2)

Answer 23

Similar to LCIS, but histologists differ based on distension of lobule (LCIS is distended).
Less risk of cancer (4-6x vs 11x with LCIS), but should be excised

Question 24

Papilloma (5)

Answer 24

Most common intraductal mass.
Most common cause of bloody discharge.
Usually seen in perimenopausal women, 1cm from nipple in 90%.
Mammogram: often normal, sometimes just calcifications.
US: Well defined smooth walled hypoechoic mass, sometimes cystic with solid components.
Usually associated duct dilatation.
Galactography: solitary filling detected with dilated duct.

Question 25

Multiple papillomas (2)

Answer 25

Tend to be more peripheral.
Mammogram: either mass (or masses) or cluster of calcifications without a mass.

Question 26

Phyllodes tumour (2)

Answer 26

10% risk of malignant degeneration.
Fast growing breast mass, occurs in older age than fibroadenomas (40-50s)

Question 27

Multiple masses (2)

Answer 27

Need at least 3 bilateral well circumscribed masses without suspicious features.
Need to be bilateral to consider them benign.