Breast imaging Flashcards
What are the imagings for breast cancer?
Mammography: 1st line
USG
MRI
What is the invasive ductal breast cancer progression?
Normal –> FEA –> ADH –> DCIS –> ICS
FEA: low grade form of atypia involving the breast acini
ADH is a proliferation of intraductal luminal cells and represents a greater degree of atypia
Upstaging refers to the dx of a higher grade malignant lesion (suc has DCIS or ICS) following surgical excision than initially diagnosed by core needle biopsy.
What are the risk factors for developing breast cancer?
2 most important factors: female sex and advancing age
Inherited BRCA1/BRCA2 mutation
1st degree relative with breast cancer
Prior chest radiation for Hodgkin or non Hodgkin lymphoma
Prior biopsy result of following high risk lesion: atypical lobular hyperplasia (ALH), lobular carcinoma in situ (LCIS), atypical ductal hyperplasia (ADH), flat eithelial aplasia, radial scar, intraductal papilloma
Long term estrogen exposure: early menarche, late menopause, late 1st pregnancy, nulliparity, or obesity (through increased estrogen exposure production by adipocytes)
What is DCIS?
Carinoma contained within the duct with an intact basement membrane in place (once tumor cells have broken through the basement membrane invasive disease is present). It represents the lowest stage of breast cancer, stage 0
DCIS is the most frequent occult cancer detected mammographically
On MRI, a pattern of linear or segmental, clumped enhancement is suspicious for DCIS
What is the most common breast cancer?
Invasive ductal carcinoma: palpable mass with classic mammographic appearance being an irregular mass with spiculated margins and associated pleomorphic calcifications.
Basal type breast carcinoma is a phenotype given to triple (ER,PR and HER2/neu) negative carcinomas due to gene underexpression. This phenotype includes different morphologic types including medullary carcinoma and invasive carcinoma in the setting of BRCA1 mutation. Although these tumors are usually high grade, basal like breast caricnomas have been associated with favorable response to neoadjuvant chemotherapy.
What are special histologic subtypes of IDC with favaroable prognosis?
- Tubular carcinoma: low grade cancer with typical architectural distortion or a small spiculated mass and accounts for <2% of invasive ductal cancers
- Mucinous carcinoma
- Medullary carcinoma
- Encapsulated papillary carcinoma
- Adenoid cystic carcinoma
What is invasive lobular carcinoma prevalence?
Presentation?
5-10% of breast cancer cases
Difficult to diagnose via mammography and clinically due to tendency to spread through the breast tissue without forming a discrete mass.
IL presents an imaging challenge due to its elusive appearance, which ranges from 1 view asymmetry to architectural distortion to a spiculated mass.
What is inflammatory carcinoma?
Aggressive form of breast cancer that represents invasion of dermal lymphatics
Presents with breast erythema, edema and firmness, oftened referred to as a peau d’orange or orange peel appearance.
Mammography: affected breast is larger and denser, with trabecular thickening and skin thickening. Primary ddx is mastitis.
What is the cause of paget disease of nipple?
Form of DCIS that infiltrates the epidermis of the nipple
Clinically, paget disease of the nipple presents with erythema, ulceration and eczematoid changes of the nipple.
What is breast cancer prognosis?
In non metastatic invasive breast cancer, axillary lymph node status is the most important prognostic factor.
Patients with ER and PR positive tumors have longer disease free survival.
Triple negative cancers are ER, PR and HER2/neu negative and majority are biolgoically aggressive with poor prognosis. Triple negative cancers account for the majority ofb reast cancer in patients with BRCA1 mutation.
What is the BI-RADS assessment categories?
Cat 0: need additional imaging
Cat 1: negative
Cat 2: benign BI-RADS2 e.g. benign calcifications, simple breast cysts, intramammary lymph nodes (no additional followup needed)
Cat 3: probably benign. <2% risk of malignancy. Necessary to conduct a complete dx imaging evaluation using diagnostic views (spot compression magnification). Action required: short interval follow up, typically 6 months. After 12 months of stabilty it is acceptable to lengthen the follow up interval to 1 year.
Cat 4: suspicious. Findings suspicious of malignancy with a probability of being malignant >2% and <95%. Divided into category 4A,B, C with 4A being least suspicious. Action required: biopsy.
Cat 5: highly suggestive of malignancy. High probability (>95%) of being cancer. BI-RADS5. Action required: biopsy
What are the routine screening mammographic views?
Additioanl views may be indicated:
Cleavage view images the medial breast tissue of both breasts
Exaggerated CC (XCC) views pulls either lateral or medial tissue into the imaging detector
What is seen?
In every mammographic report, the mammographic pattern of fibroglandular density should be characterized into one of the above descriptors.
Women with dense fibroglandular tissue have an increased risk of developing breast cancer, and detection of early cancer can be obscured by the fibroglandular tissue. A woman with extremely dense breasts has a 5x relative risk of breast cancer compared to a woman with almost entirely fatty breasts.
Edema due to systemic causes, such as congestive heart failure, typically causes bilateral trabecular blurring and skin thickening.
Hormone therapy may cause an increase in fibroglandular density, without skin thickening. Proliferation of cysts and fibrocystic change can be seen, even in postmenopausal women.
Pregnancy, lactation, and weight loss may all cause an interval increase in fibroglandular density.
What are benign causes of skin thickening?
- Radiation therapy (usually unilateral).
- Acute mastitis (usually unilateral).
- Skin inflammation (usually unilateral and focal).
- CHF (fluid overload), renal failure (fluid overload due to protein wasting), and liver failure (fluid overload due to hypoalbuminemia) may all produce unilateral or bilateral skin thickening.
What are malignant causes of skin thickening?
- Inflammatory carcinoma, which represents invasion of dermal lymphatics by cancer. A mammographic mass may be present.
- Locally advanced carcinoma.
- Lymphatic obstruction from axillary adenopathy.
What is the lexicon for evaluating margins using BI-RADS?
Circumscribed: at least 75% of the margin must be well defined, while the remainder may be obscured with overlying tissue
Microlobulated
Obscured: mass obscured by more than 25%
Indistinct: poorly defined margin raises concern that the lesion may be infiltrating.
Spiculated: linear densities radiate from a mass. A spiculated mass is malignant until proven otherwise
How to describe the density of mass using BI-RADS?
Most breast cancers that form a visible mass are of equal or high density than the surrounding fibroglandular tissue.
A circumscribed fat containg mass is benign.
How to describe the shape of mass using BI-RADS?
What are the 4 things that must be commented on in BI-RADS for mammographic mass?
