Breast Anatomy & Benign Breast Conditions Flashcards
breast anatomy - overview
*breast is a modified sweat gland
*hormone-mediated growth and development
*estrogen stimulate proliferation of the duct system of the breasts during puberty
*breast develops from milk line (axilla to vulva)
-pathologies: extra nipples, extra tissue, etc
breast anatomy - detailed
*each breast (mammary glands) contains 15-20 lobes
*upper outer quadrant has highest density of lobes (& pathology)
*each lobe is comprised of many lobules
*lobules have glands (acini) that make milk, which drains through ducts out to nipple
terminal duct lobular unit (TDLU) of breast
*TLDU is the functional unit of the breast
*comprised of 10-100 sac-like acini in each lobule that open into the terminal duct
*terminal duct → larger ducts → main duct of the lobe → nipple
*most pathologic changes in the breast are believed to arise from the TLDU
epithelium in ducts & lobules of breast
*ducts and lobules are lined by 2 epithelial layers:
1. luminal cell layer - makes the milk in lobule; protects the duct
2. myoepithelial cell layer - contractile function = squeeze duct to move milk, give glands and ducts structure
inflammatory benign breast conditions
- acute bacterial mastitis
- periductal mastitis
- mammary duct ectasia
acute bacterial mastitis - cause
*breastfeeding → fissures in nipple + blocked duct → bacteria (Staph aureus) enters duct → infection & inflammation
*affects 2-10% of breastfeeding women
acute bacterial mastitis - clinical presentation
*warm, erythematous, painful breast (unilateral)
*most common in first 3 months of breastfeeding
*sometimes with fevers or purulent nipple discharge
acute bacterial mastitis - treatment
*continue to breastfeed / drain breast
*NSAIDs/cold compresses = initial treatment
*if symptoms persist after 24 hours, consider antibiotics depending on severity (DICLOXACILLIN)
*can progress to abscess/mass if not treated
periductal mastitis - overview
*inflammation of subareolar duct
*smoking causes a relative vitamin A deficiency; vitamin A is needed to protect the Luminal Cell layer; without vitamin A, the specialized double epithelium of breast ducts becomes squamous, and produces a keratinized plug, causing inflammation
periductal mastitis - clinical presentation
*periareolar inflammation
*subareolar mass
*nipple retraction
*usually seen in older smokers
*mass can form abscess
*abscess can result in fistula formation
periductal mastitis - treatment
*antibiotic for periductal infection
*abscess can get incised & drained
*condition may be chronic and may warrant excision of diseased duct
*must rule out more sinister cause of mass (cancer)
mammary duct ectasia - cause
*distension/dilatation (ectasia) of subareolar ducts
*inflammatory debris builds up in duct and leaves nipple as green/brown discharge
*blocked duct can lead to infection / mastitis / abscess
mammary duct ectasia - clinical presentation
*usually presents in multiparous postmenopausal women
*green / brown / thick white nipple discharge
*often presents with poorly palpable periareolar mass
*if fluid in mass is dark, can present as a blue mass under the nipple (“blue breast”)
*relatively rare
mammary duct ectasia - diagnosis / treatment
*ultrasound can help make dx
*biopsy will show chronic inflammation (plasma cells)
*often resolves spontaneously
*can be excised surgically if it does not resolve
*NOT breast cancer
fat necrosis of the breast - cause
*necrosis of breast fat after tissue injury / trauma to the breast
*usually follows a trauma or surgical intervention
*saponification of fat cells → addition of calcium to fat
fat necrosis of the breast - clinical presentation
*painless palpable mass, skin thickening or retraction
*can mimic malignancy on exam/mammo
*biopsy shows necrotic fat / calcification / giant cells
fat necrosis of the breast - treatment
*excision not necessary
*no increased breast cancer risk
intraductal papilloma - overview
*BENIGN tumor of the milk ducts of the breast
*finger-like lesion within the duct, lined with epithelial cells (both cell layers: luminal and myoepithelial)
*classically present with unilateral bloody nipple discharge
intraductal papilloma - clinical presentation
*seen in pre-menopausal women
*bleeding of papilloma results in bloody nipple discharge
*usually develops in more distal (close to nipple), large ducts of breast
*must distinguish from papillary carcinoma on biopsy (post-menopausal)
*not concerning in and of themselves, but can harbor atypia so small risk of developing into cancer
fibroadenoma - overview
*benign overgrowth of fibrous tissue and glandular tissue in lobule
*no increased risk for breast carcinoma
fibroadenoma - clinical presentation
*most common benign solid breast mass
*usually presents in adolescents and young adults (most common in women < 30 years)
*estrogen sensitive - grow during pregnancy, shrink during menopause; fluctuate in size with menstrual cycle
*well-circumscribed, mobile, marble-like, rubbery, slow-growing
*upper outer quadrant of breast
Phyllodes tumor - overview
*uncommon tumors that arise from the intralobular stroma that surrounds the breast ducts & lobules
*Phyllodes = resembling a leaf
*similar to fibroadenoma, but relative overgrowth of fibrous component pushes tumor out in leaf-like projections
