Breast Pathology Flashcards
Breast Development
- Mammary ridges along body at 15 wks gestation then involute everywhere but typical breast area
- At term, 15-25 mammary ducts and sebaceous glands that come together near epidermis
- Glands cont to grow in proportion to body growth in both
genders - Right b/f puberty, duct system grows more rapidly in girls in response to estrogen
- During puberty, extensive growth, branching, canalization of lobular-alveolar units at tips of branches (cont thru pubertal development)
Basic Breast Histology / Anatomy
- 8-10 large ducts starting at nipple –> terminal ducts w/ lobules
- Intralobular stroma - loose stroma immediately around lobules
- Interlobular stroma - fat-predominant outside ductal system
- Ea gland surrounded by 2 cell layers - basal cell layer (spindle, myoepithelial for contraction) and luminal cell layer (cuboidal, plump) w/ loose stroma b/n individual glands
How does breast tissue look during pregnancy?
Adenosis (inc glands) and foamy secretions
Traumatic Fat Necrosis
- Mimics carcinoma clinically - local swelling +/- bruising
- Usually follows trauma (seatbelt in car accident)
- Resolves spontaneously
- Chronic inflammatory cells and macrophages +/- multi-nucleated giant cells
Fibrocystic Change
- COMMON (50% women)
- Sex steroid hormone responsive
- Proliferative (>2 cell layers) v non-proliferative (no inc risk)
- Grossly - cysts surrounded by white/tan fibrotic area
- Histo - swollen/dilated cysts, adenosis (inc glands), PINK fibrosis, apocrine change in cells lining glands (metaplasia)
- Apocrine metaplasia = still have single basal layer but luminal layer has extensions of cytoplasm (“cytoplasm snouts”)
Fibroadenoma
- COMMON (in young women)
- Inc in loose intralobular stroma that then compresses lobule epithelium
- Grossly - very well demarcated
- Histo - uniform stroma proliferation around glands
BENIGN; NO INC RISK CANCER
Gynecomastia
- Small, sub-areolar swelling (usually bilateral)
- Causes -
- Drugs - estrogem , digitialis, spironolactone
- Cirrhosis, malnutrition
- Estrogen secreting tumor or Leydig cell tumor
- Klinefelter’s
- No clear assn w/ breast cancer
- Histo - epithelial hyperplasia (> 2 cell layers) w/ halo around ducts from periductal edema
Intraductal Papilloma
- Fibrovascular core - see pink fibers and vessels w/in duct lumen
- Can cause bloody nipple d/c
Sclerosing Adenosis
- inc # glands but contained w/in same lobule shape / pattern
- Only inc risk cancer if proliferative (proliferative if > 2 cell layers)
Ductal Hyperplasia
- Can be mild (no inc risk), moderate (1.5 - 2X inc risk) or atypical (4-5X inc risk)
- Atypia = more blue (nuclei) and bridging b/n adjacent cells
LCIS
(general bilateral risk –> ductal carcinoma)
- Preserved myoepithelial cell layer; still has BM; confined to ducts
- More often multifocal and bilateral
- Usually not associated w/ micro-calcifications on Xray but found incidentally
- Histo - fills duct so do not even see lumens, no room for central comedonecrosis
- E-cadherin -
DCIS
(ipsilateral risk)
- Preserved myoepithelial cell layer; still has BM; confined to ducts
- Most commonly associated w/ micro- calcifications on XRay
- Histo - cookie-cutter punches out areas; comedonecrosis (pink material w/o nuclei in lumen) and calcifications
Invasive Ductal Carcinoma
- No myoepithelial cell layer (lose p63 stain marker); haphazard invasion into surrounding stroma
- Histo - areas of necrosis, atypia (nucleoli, mitoses, pleomorphism); nests of cells (not straight lines)
- E-cadherin + (maintain tight junctions)
Invasive Lobular Carcinoma
- Less common than ductal
- Histo - targetoid / linear appearance (“indian file”); not as haphazard; tumor cells in straight lines; cells have more abundant cytoplasm and nuclei pushed to side; bland cells
- E-cadherin -
3 Ductal Carcinoma Variants
ALL HAVE GOOD PROGNOSIS
1 - Mucinous - see tumor cells floating in mucin
2 - Tubular - low-grade atypia (look normal) but lose basal cell layer so only 1 cell layer (p63-); angulated glands
3 - Medullary - sheets of tumor cells
Phyllodes Tumor
- Borderline or malignant variety of fibroadenoma (INTRALOBULAR STROMA AFFECTED)
- More blue stroma and atypia
Angiosarcoma
- Mesenchymal tumor primarily in young pts
- Stewart-Treves Syndrome - angiosarcoma in skin of pt w/ lymphedema after mastectomy (5-10 yrs after tx)
What types of lymphomas are associated w/ breast?
- Primary (NHL, MALT, Burkitt); all B cells
- Secondary
- Anaplastic large cell lymphomas associated w/ breast implants; chronic inflammatory reaction w/ abnormal T cells
- Serous fluid (present w/ swelling) - when drain notice it is lymphoma
Paget’s Disease of Breast
- In situ carcinoma of lactiferous ducts w/ extension into epidermis
- Eczema-like rash (excoriations), d/c, crusting
- 95% associated w/ underlying ductal type carcinoma
- Histo - large cells w/ abundant cytoplasm
- R/o melanoma
General Risk Stratification
Non-proliferative Lesions = no inc risk invasive carcinoma
- Cysts
- Papillary apocrine change
- Mild hyperplasia
Proliferative W/o Atypia = 1.5 to 2X higher risk
- Moderate (florid) Ductal Hyperplasia
- Intraductal Papilloma
- Proliferative Sclerosing Adenosis
- Complex Sclerosing Lesions
- Complex Fibroadenomas
Atypical Hyperplasia or Proliferative w/ Atypia = 4-5X higher risk
- Atypical Ductal Hyperplasia
- Atypical Lobular Hyperplasia
Carcinoma In Situ = 8-10X higher risk
