4.8 Breast

Question 1

Breast Anatomy - blood and LN drainage

Answer 1

Develops from upper third of mammary ridge between upper and lower limb buds
Clavicle to 8th rib, sternum to mid-clavicular line; Contains 20 lobes, each made up of lobules (each 500 microns, smallest structural unit of breast)
Terminal duct (origin of breast cancers) lobular unit - branches of major duct and its lobule
TDLU epithelium has 2 layers - luminal true epithelial and deep myoepithelial
Arterial supply (venous drainage follows same pattern)
UOQ - lateral thoracic artery (br of axillary),
medial / central - internal mammary (subclavian), 
lateral -  intercostal arteries
Lymph - mainly to axillary (75%), internal mammary (25%) and upper abdomen

Question 2

Implant rupture - site, risk, imaging

Answer 2

1-2% of implants rupture
Extracapsular (implant shell and fibrous capsule) - snowstorm
Intracapsular (implant shell only) - stepladder pattern, may also diplay ‘linguini sign’
Inverted tear drop - gel bleed between inner and outer capsule

Question 3

Mammography views

Answer 3

Should have fat visible behind glandular tissue on all views
MLO (40-60 degrees) - should have pectoralis to level of or below nipple axis, should appear convex
CC - usually allows better compression, pectoralis visible on 35%, pec-nipple distance on CC should be less than or equal to 1cm of MLO distance
XCCL - exaggerated craniocaudal - views axillary tail of Spence
True lateral - ML and LM for lesion localisation
Cleavage valley - between breasts
Spot compression and magnification - further evaluation of lesion margins, regions of tissue distortion
Tangential - for skin lesions
Rolled - if lateral roll, superior lesion moves laterally, if medial roll, superior lesion moves medially

Question 4

Mammography tube, purpose of compression

Answer 4

Lesion movement from MLO to lateral - medial lesions move up, lateral lesions move down
Mo anode with 17.9 and 19.5 keV peaks, Mo filter excludes >20 keV
Tube windows - Be (less filtration)
Compression - reduces blur, dose, motion, exposure time, scatter; improves resolution and separates overlapping structures

Question 5

Standard mammographic views for implants

Answer 5

CC, MLO, Implant displaced CC and MLO (Ecklund)

Question 6

Evaluation of mammogram

Answer 6

Quality and penetration
Skin, nipple and trabecular changes
Presence of masses and calcifications
Axillary nodes
Asymmetry
Architectural distortion
Signs of malignancy = spiculated / ill-defined mass, clustered microcalcifications, enlarged LNs

Question 7

Signs of malignancy on Mammogram

Answer 7

Margins: Spiculation (also seen in scar tissue - resolves in less than 1 yr if surgical, 3 yrs if radiation; desmoid tumours and fat necrosis); Indistinct (also fat necrosis, elastosis, infection, haematomas); Microlobulation; Obscured; Circumscribed with well-defined borders
Size
Irregularity
Density (malignant usually very dense)
Location
Multiplicity - multiple lesions likely FAs or cysts
Calcifications (reason for detection of 50% of cancers)

Question 8

BIRADs Categories

Answer 8

0 = inconclusive
1 = negative
2 = benign
3 = probably benign (less than 2% risk malignacy) - 6 month follow-up
4 = suspicious; consider biopsy
5 = cancer >95% certainty; needs biopsy / excision
6 = biopsy proven malignancy

Question 9

Malignant features of calcifications

Answer 9

Size less than 1 mm
Less than 5 calcs/cm3
Clustered (not scattered)
Wild, fine linear branching (dot-dash)

Question 10

Breast calcifications types

Answer 10

Popcorn - involuting fibroadenoma, rarely a papilloma
Fine curvilinear - walls of round mass, usually benign cyst
Dense lucent centred - fat necrosis
Linear / parallel - vascular
Calcified rods - secretory disease
Pleomorphic - less than 0.5 mm and with mass = intraductal cancer
Fine linear - comedonal carcinoma

Question 11

Breast MRI - timing, malignancy

Answer 11

Days 7-14 best (less physiological enhancement)
Round / oval lesions with non-enhancing septations almost always fibroadenoma
Heterogeneous and peripheral enhancement most common in malignant lesions
Cancer usually low signal on T2W

Question 12

Enhancing breast lesions on MRI

Answer 12

Cancer
Fibroadenomas
Fibrocystic change (including sclerosing adenosis)
Fat necrosis
Radial scars
Mastitis
Atypical hyperplasia
Lobular neoplasia
Normal breast tissue

Question 13

Breast cysts - definition, association, imaging

Answer 13

Usually dilatation of lobular acini, less often distended ducts; less than 3 mm microcyst, >3 mm macrocyst
Rarely (less than 0.2%) associated with intracystic papillary carcinoma
Mammo: Usually well defined but margins may be obscured due to pericystic inflammation, ±lucent halo (Mach effect)
Eggshell wall calcification; milk of calcium (concave crescent) on lateral, amorphous dots on CC
MR: Rarely demonstrates rim enhancement due to pericystic inflammation

Question 14

Fibrocystic breast disease - risk

Answer 14

Can indicate increased risk of malignancy
Atypical hyperplasia x5 risk
Hyperplasia, sclerosing adenoma (x2)
No increased risk with cysts, FA, Fibrosis, Adenosis, duct ectasia, Mastitis, metaplasia

Question 15

Fibroadenoma - CFs, imaging

Answer 15

Commonest benign breast lesion, usually less than 40 y/o, moblie, may have thin lucent halo
Calcification: usually popcorn (pathognomic) but can be fine and irregular (like malignancy)
US: Ovoid, hypoechoic, can have irregular internal echo pattern, can show posterior enhancement or shadowing (if fibrosis), can show lateral wall refractive shadowing
MR: T1W hypointense, T2W hyperintense, Usually enhances but non-enhancing septations are daignostic
Juvenile FA (giant FA) more cellular variant, usually at 10-20 y/o

Question 16

Phyllodes tumour - CFs, imaging, metastases location

Answer 16

AKA cystosarcoma phyllodes; Rare, 30-50 y/o, rapidly enlarging, mobile, usually benign stromal tumour with 25% recurrence if incomplete excision
10-15% malignant with lung metastases
Malignant tumours likely if > 3 cm, contain sarcomatous elements (10% of phyllodes show haematogenous metastasis)
No spiculation and no microcalcification
US: large, well circumscribed, low amplitude internal echoes, can have posterior enhancement or attenuation
MR: rapid enhancement, indistinguishable from fibroadenoma

Question 17

Adenosis - definition

Answer 17

Proliferation of glandular structures
Formation of new ductules and lobules
Terminal intralobular ducts with proliferation of epithelium
Overgrowth of myoepithelial cells

Question 18

Pseudoangiomatous Stromal Hyperplasia (PASH) - definition, US

Answer 18

Benign proliferative lesion of mammary stroma, particularly myofibroblasts
Hypoechoic
May grow / recur following excision

Question 19

Gynaecomastia - definition, causes

Answer 19

True: increase in number ±dilatation of ducts, can be unilateral or bilateral
Pseudogynaecomastia: purely fat deposition

Question 20

Gynaecomastia - causes

Answer 20

Hormones, liver failure (inadequate oestrogen degradation)
Drugs: reserpine, digoxin, spironolactone, cimetidine, thiazides, marijuana
Testicular tumours: seminoma, choriocarcinoma, embryonal cell carcinoma
Kleinfelters (increased risk breast cancer)
Lung cancer

Question 21

Intraductal papilloma - CFs, imaging

Answer 21

Common cause of bloody / serous nipple discharge
Generally benign ductal epithelium proliferation, projects into duct, has fibrovascular stalk; can’t determine if malignant on imaging
Usually solitary (in peri-/postmenopausal, usually subareolar region)
If multiple (younger) tend to be in smaller peripheral ducts, higher risk of atypical changes / carcinoma
Mammo: only visible if in anterior part of breast, can cause non-specific microcalcifications or ‘shell-like’ lucent subareloar calcifications
US: solid, hypoechoic, lobulated, occasionally in cystically dilated duct
MR: ±enhancement

Question 22

Lipoma - imaging

Answer 22

Superficial, peripheral, always encapsulated, mobile
Mammo: Radiolucent ±thin capsule, can distort parenchyma / be moulded; can show spherical calcification of fat necrosis
US: hypoechoic ±specular reflection from capsule
MR: similar to surrounding breast fat

Question 23

Focal fat necrosis

Answer 23

Palpable mass, may be hard, can show irregular clustered calcification (similar to malignancy)

Question 24

Galactocoele - definition, imaging

Answer 24

Milk containing cystic structure
Mammo: usually radiolucent with dense surrounding lactating tissue, ±fat-fluid level
US: variable, thin walls ±internal echoes ±shadowing

Question 25

Hamartoma - definition, CFs, imaging

Answer 25

AKA fibroadenolipoma, proliferation of fibrous and adenomatous nodular elements, surrounded by capsule of connective tissue 3-5 cm, 75% palpable Mammo: sharply marginated, may appear similar to lipoma, ±visible capsule US: sharply defined, displaces surrounding structures, heterogeneous echo pattern

Question 26

Radial scar - definition, imaging

Answer 26

Idiopathic scar-like lesion, requires biopsy Mammo: Architectural distortion with spiculation ±microcalcifications, usually no mass, indistinguishable from cancer US: Irregular, poorly defined, hypoechoic MR: may appear similar to cancer

Question 27

Duct ectasia - location, imaging

Answer 27

Usually in subareolar major ducts, non-specific duct dilatation ±thickened ducts due to periductal collagen deposition Mammo: Tubular serpiginous structures converging on nipple in subareolar region ±rod shaped calcifications ±central lucency, may also appear as spherical / globular densities with central lucencies US: Duct containing debris - homogeneous solid tubular structure or tubular anechoic branching structure

Question 28

Breast abscess - association

Answer 28

Can look solid or cystic on US, usually young nursing mothers

Question 29

Ductal carcinoma - source, frequency, imaging

Answer 29

From ductal epithelium, 90% breast cancer DCIS if confined to duct, 30-50% proceed to invasive ductal carcinoma (breaches basement membrane of duct) Mammo: Fine linear branching calcifications MR: not always visible, usually pronounced segmental enhancement

Question 30

Invasive ductal carcinoma - CFs, imaging

Answer 30

Palpable mass, desmoplastic reaction, cictrisation, fibrosis ±ulceration through skin Mammo: irregular mass, spiculated margin, calcification, architectural distortion, skin/nipple retraction, may be undetectable if surrounding breast same density as tumour US: Irregular, hypoechoic, retrotumoural shadowing, vertically orientated relative to skin MR: Irregular enhancing mass with rapid enhancement then plateau / rapid washout ± peripheral enhancement Well differentiated form is Tubular cancer, slow growing spiculated lesion, rarely spreads to axillary LNs

Question 31

Paget's disease of breast - definition, imaging

Answer 31

Ductal carcinoma involving nipple, usually no evident tumour mass, good prognosis, US usually not indicated Mammo: may be normal, occasionally microcalcification in subareolar region directed towards nipple

Question 32

Papillary carcinoma - definition, imaging

Answer 32

Ductal epithelium proliferates into villous projections, fills lumen, slow growing Mammo: Well circumscribed mass, lucent halo, can occur within a cyst US: Complex solid or cystic mass, may shows as fronds projecting into a cyst

Question 33

Colloid / Mucinous carcinoma - definition, imaging

Answer 33

Form of ductal carcinoma with mucinous differentiation Mammo: Similar to other cancers but often lower density and well circumscribed, ±lobulation US: Hypoechoic MR: high signal T2W, lobulated with slow contrast enhancement

Question 34

Medullary carcinoma - CFs, imaging

Answer 34

Incidence peaks in 20's, large, soft, movable tumour Mammo: Well-circumscribed, smooth, ill-defined margin US: Hypoechoic ±heterogeneous internal echoes, often posterior acoustic enhancement MR: round, well-defined borders, diffuse enhancement

Question 35

Inflammatory carcinoma - CFs, imaging

Answer 35

Warm, erythematous, peau d'orange, painless, peaks at 30 y/o Mammo: Skin thickening, usually no mass or calcifications, increased density on affected side due to trabecular thickening US/MR no distinctive features

Question 36

Lobular carcinoma - definition, imaging

Answer 36

Cells similar to those lining lobules, LCIS if confined to lobule, LCIS increases risk of invasive loblular carcinoma in both breasts LCIS usually younger women with dense breasts, has lower risk of becoming invasive than DCIS Usually no specific finding on mammo or US but adjacent benign tissue often has calcification

Question 37

Invasive lobular carcinoma - CFs, imaging

Answer 37

Usually large, often bilateral, insidious onset, less desmoplastic responese than ductal cancer Mammo: early detection hard, usually asymmetric breast density / area of increasing density US: Hypoechoic with variable posterior acoustic shadowing MR: Similar enhancement to invasive ductal carcinoma

Question 38

Breast cancer mimics

Answer 38

``` Post surgical scarring Radial scars Fat necrosis Extra-abdominal desmoid tumours (rare) Granular cell tumours (very rare) ```

Question 39

Mastitis - cause

Answer 39

Acute = puerperal, usually staphylococcus Nonpuerperal - older patients, can form abscess Plasma cell mastitis - rare aseptic subareolar inflammation, usually bilateral and symmetrical Granulomatous (rare) - TB, sarcoid

Question 40

Stereotactic biopsy - indications

Answer 40

For lesions only visible on mammography

Question 41

Commonly missed lesions on mammography

Answer 41

Invasive lobular carcinoma - only architectural distortion and asymmetric density visible Invasive ductal carcinoma - commonest well-circumscribed lesion DCIS coexisting with atypical ductal hyperplasia on bx Palpable mass - may require spot film

Question 42

Postradiation breast - imaging features

Answer 42

Usually 50 Gy total, with 60-75 Gy boosting at lumpectomy site Diffusely dense breast most pronounced at 6 months, almost gone after 24 months Thickening of skin and trabecula, usually resolves in months, may progress to fibrosis Calcifications Residual tumour (although should be surgically removed originally) Benign dystrophic calcification (arise at 2 to 4 years, usually benign with central lucency)