Pathology of the breast Flashcards
1
Q
Anatomic locations for breast lesions
A
- Paget’s disease: nipple and areoli
- Nipple adenoma: lobar ducts (btwn lactiferous sinus and nipple)
- Papillomas: lactiferous (major) ducts
- Traumatic fat necrosis: periphery of breast (fat pad)
- Hyperplasia, CA, cysts, fibroadenomas: usually in periphery (glandular tissue) and TDLU (lobule and/or terminal duct)
2
Q
Fibrocystic change 1
A
- Non-neoplastic, benign lesion of the breast, very common
- Affects multiple areas of breast bilaterally
- Presents as lumpy-bumpy nodular masses and changes w/ menstrual cycle
- Micro of non-proliferative: fibrosis of storma, variably sized terminal duct cysts, apocrine metaplasia, increased lymphocytic infiltrate
3
Q
Fibrocystic change 2
A
- In proliferative change there’s additional findings: either ductal hyperplasia w/o atypia (lumen epithelial layer is still simple epithelium) or with atypia (lumen epithelia becomes stratified)
- W/o atypia has 2 fold increase risk of CA, but w/ atypic there is 4-5 fold increased risk for CA
- There may also be sclerosing adenosis of the TDLU/small ducts, characterized by prominent intracellular fibrosis (may be misdiagnosed by CA)
4
Q
Mastitis 1
A
- Acute: bacterial infection of the breast, most frequently in postpartum lactation
- Secondary to nipple cracking/fissuring, most commonly from staph/strep
- Staph infections may progress to abscess formation
- Signs: acute inflammation grossly and PMNs under micro
- Granulomatous mastitis (rare): associated w/ mycobacterial, fungal, or systemic granulomatous diseases (sarcoid), also can be from leakage of silicone implants
- Histo: giant cells, macs, granulomas
5
Q
Mastitis 2
A
- Fat necrosis: usually secondary to Hx of trauma, surgery
- Small palpable mass +/- pain
- Histo: necrotic fat cells surrounded by lipid-laden and hemosiderin-laden macs and PMNs
- Followed by lymphocytic infiltration and fibrosis to wall off, then replaced by scar tissue (calcification common)
- Results in irregular, fixed, hard palpable mass that can resemble breast CA (must distinguish)
6
Q
Fibro-adenoma
A
- Neoplastic, benign proliferation of stromal and glandular tissue
- Tend to be in young women and multiple/bilateral
- On palpation its a discrete, nodular/lobulated, rubbery lesion (highly variable size) that is freely movable and well circumscribed
- Histo: stroma demonstrates a myxoid (more common) or fibrous/hyaline appearance, ductal epithelium often have nl appearance w/ hyperplastic cell layers
- Ductal epithelium may be attenuated (irregular slit-like structures) due to compression from surrounding stroma
7
Q
Papilloma
A
- Benign papillary neoplasm arising in duct
- Central fibrovascular stalk extends from wall and branches into multiple projections
- Most tumors are solitary and occur in lactiferous ducts
- Clinical: bloody or serous nipple discharge
8
Q
Risk factors for developing breast CA
A
- 2 most important ones: female and old age (>50)
- Others: early menarche, late menopause, nulliparous, lack of breast feeding, lack of physical exercise, family Hx (BRCA1/2, li-fraumeni)
- 99% of cancers are carcinomas (origins in ducts or lobules), 1% are sarcomas
9
Q
Pathways for developing breast CA
A
- Hormonal stimulation (E+P) causes breast cell proliferation-> DNA replication errors/mutations
- 3 types of breast CAs: ER+ (HER2-), HER2+ (ER+/-), and ER- (HER2-)
- HER2+ is overexertion of HER2
- These different types are important for Rx of the CA
- Most CAs are found by abnormal mammograms
10
Q
Ductal CA in situ (DCIS)
A
- Malignant ductal epithelial cells limited to ducts and lobules (intact duct/lobule basement membrane)
- Several different patters, most cases are mixed
- Comedo: central necrosis often w/ micro calcifications
- Solid: cells completely fill duct
- Cribiform: cells are separated and sharply defined, regularly distributed spaces (look like mini-ducts w/in duct filled w/ cells)
- Micropapillary: papillary projections in the lumen of the duct (no fibrovascular core)
11
Q
Paget disease of the breast
A
- Uncommon variant of DCIS or ductal CA in which there is intraepidermal spread of malignant cells from lactiferous ducts to nipple surface
- Tumor cells (paget cells) that migrate out the duct to the surface disrupt the normal squamous epithelium, resulting in seepage of fluid onto nipple and areola
- If an erythematous nipple surface w/ weeping, scaly crust is present (mimic eczema) in a pt w/ underlying palpable mass (1/2 of pagets pts have masses) then think paget’s disease
12
Q
Lobular CA in situ (LCIS)
A
- Almost always incidental finding on Bx, seldom associated w/ stream rxn or calcifications (usually no mammography of PE findings)
- Small, round, uniform, and loosely cohesive cells pack and distend acini (do not create palpable mass)
- Lesions are often multifocal, bilateral and increase risk of invasive CA in either breast
13
Q
Invasive ductal CA 1
A
- 80% of invasive breast CA (invasive breast CA 80% of total breast CA, other 20% are CA in situ)
- Lesions do not have consistent histo findings, clinically more aggressive
- Can be well-differentiated: resembles well-formed glands
- Can be poorly differentiated: cords or solid sheets of epithelial cells
- Often are accompanied by various grades of DCIS
- Usually does present as a hard, fixed mass on palpation (scirrhous breast CA)
14
Q
Invasive ductal CA 2
A
- Advanced disease may be associated w/ swollen, dimpled, and thickened overlying skin from stromal infiltration and lymphatic obstruction (peau d’orange)
- Picked up as mammography densities +/- calcifications
- Well-differentiated tumors typically express hormone (E/P) receptors and are HER2-
- Reverse is true for poorly differentiated CAs (but there can be both)
15
Q
Invasive lobular CA
A
- 10% of invasive breast CA
- Cells are morphologically similar to those in LCIS w/ diffuse invasion patter
- Classic findings: short, single-file chain or strands of cells infiltrating btwn collagen fibers
- Mucin-producing variant may lead to signet ring appearance
- Cells are indistinguishable from LCIS and often accompanied by adjacent LCIS
- 75% present similarly to ductal CA (palpable mass and mammography densities), but 25% have diffuse (occult) disease
- Vast majority are ER/PR+ and HER2-
