4.8 Breast Flashcards
Breast Anatomy - blood and LN drainage
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
Implant rupture - site, risk, imaging
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
Mammography views
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
Mammography tube, purpose of compression
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
Standard mammographic views for implants
CC, MLO, Implant displaced CC and MLO (Ecklund)
Evaluation of mammogram
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
Signs of malignancy on Mammogram
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)
BIRADs Categories
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
Malignant features of calcifications
Size less than 1 mm
Less than 5 calcs/cm3
Clustered (not scattered)
Wild, fine linear branching (dot-dash)
Breast calcifications types
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
Breast MRI - timing, malignancy
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
Enhancing breast lesions on MRI
Cancer Fibroadenomas Fibrocystic change (including sclerosing adenosis) Fat necrosis Radial scars Mastitis Atypical hyperplasia Lobular neoplasia Normal breast tissue
Breast cysts - definition, association, imaging
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
Fibrocystic breast disease - risk
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
Fibroadenoma - CFs, imaging
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
Phyllodes tumour - CFs, imaging, metastases location
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
Adenosis - definition
Proliferation of glandular structures
Formation of new ductules and lobules
Terminal intralobular ducts with proliferation of epithelium
Overgrowth of myoepithelial cells
Pseudoangiomatous Stromal Hyperplasia (PASH) - definition, US
Benign proliferative lesion of mammary stroma, particularly myofibroblasts
Hypoechoic
May grow / recur following excision
Gynaecomastia - definition, causes
True: increase in number ±dilatation of ducts, can be unilateral or bilateral
Pseudogynaecomastia: purely fat deposition
Gynaecomastia - causes
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
Intraductal papilloma - CFs, imaging
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
Lipoma - imaging
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
Focal fat necrosis
Palpable mass, may be hard, can show irregular clustered calcification (similar to malignancy)
Galactocoele - definition, imaging
Milk containing cystic structure
Mammo: usually radiolucent with dense surrounding lactating tissue, ±fat-fluid level
US: variable, thin walls ±internal echoes ±shadowing
Hamartoma - definition, CFs, imaging
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
Radial scar - definition, imaging
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
Duct ectasia - location, imaging
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
Breast abscess - association
Can look solid or cystic on US, usually young nursing mothers
Ductal carcinoma - source, frequency, imaging
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
Invasive ductal carcinoma - CFs, imaging
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
Paget’s disease of breast - definition, imaging
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
Papillary carcinoma - definition, imaging
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
Colloid / Mucinous carcinoma - definition, imaging
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
Medullary carcinoma - CFs, imaging
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
Inflammatory carcinoma - CFs, imaging
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
Lobular carcinoma - definition, imaging
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
Invasive lobular carcinoma - CFs, imaging
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
Breast cancer mimics
Post surgical scarring Radial scars Fat necrosis Extra-abdominal desmoid tumours (rare) Granular cell tumours (very rare)
Mastitis - cause
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
Stereotactic biopsy - indications
For lesions only visible on mammography
Commonly missed lesions on mammography
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
Postradiation breast - imaging features
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)