Extend from deep pec fascia to superficial derm fascia and provide structural support to the breast. Traction on Cooper's ligaments -> skin dimpling in breast cancer
Where do 50% of breast cancers occur?
in the upper outer quadrant
How does breast cancer metastasis to the spine occur?
Venous drainage through Batson's plexus
Long thoracic nerve
Innervates serratus anterior. Injury -> winging of scapula
Innervates latissimus dorsi. Injury -> cannot push oneself up to sitting position
Medial and lateral pectoral nerves
Innervate pec major and minor. Injury -> weakness of pec muscles
Crosses axilla transversely to supply inner aspect of arm. Injury -> area of anesthesia on inner arm
Staph or strep usually. Usually during early weeks of breastfeeding. Continue breastfeeding, give dicloxicillin, drain abscess if present
Superficial thrombophlebitis of lateral toracic or thoracoepigastric vein -> acute pain in axilla or superior aspect of lateral breast. Tender cord palpated on exam. Dx: US. Tx: salicylates, warm compresses. If no resolution can resect vein.
Mammary duct ectasia (plasma cell mastitis)
Inflammation and dilation of mammary ducts. Most commonly occurs in perimenopausal years. Presents with *noncyclical* breast pain with lumps under nipple/areola +/- discharge. Dx: excisional bx to r/o cancer. Tx: excision of affected ducts.
Variant of fibroadenoma, most are benign. Presents later > 30 yrs old. Distinguishable from fibroadenoma only by biopsy. Tx: small tumors excise with 1 cm margin, large tumors do mastectomy.
Benign local proliferation of ductal epithelial cells. Presents with unilateral bloody discharge. Dx: pathologic eval. Tx: Excision of affected duct.
Ductal carcinoma in situ (DCIS) features
Sometimes there is a palpable mass. On mammo, clustered microcalcifications. Increased risk in ipsilateral breast, usu in same quadrant. If small, lumpectomy +/- rads. If large ( > 2 cm), lumpectomy + rads. If diffuse, simple mastectomy.
Lobular carcinoma in situ (LCIS) features
Never clinically detectable, usually not seen on mammo and just incidentally found on biopsy. Increased risk in both breasts. Tx: b/l mastectomy only if pt high risk.
Infiltrating ductal carcinoma
Most common invasive breast cancer (80%). Mets to axilla, bones, brain, liver, lungs.
Infiltrating lobular carcinoma
Second most common invasive breast cancer. 20% have cancer in contralateral breast as well. Lacks microcalcifications and is often multicentric. Mets to axilla, meninges, serosal surfaces.
Paget's disease of the nipple
2% of all invasive breast cancers. Presentation: tender itchy nipple +/- blood discharge +/- subareolar palpable mass. Usu assoc with underlying LCIS or ductal carcinoma.
Paget cells are large cells with clear cytoplasm and eccentric, hyperchromic nuclei found throughout the epidermis. Controversy as to their origin.
Inflammatory breast carcinoma
2-3% of all invasive breast cancers. Most lethal breast cancer-majority have mets at time of presentation. Presents with "peau d'orange" skin. Tx with chemo followed by surgery and/or rads.
Breast cancer in pregnant women
Mammography possible with proper shielding. Radiation tx no advisable so do modified radical mastectomy rather than lumpectomy + ax nod dissection + rads. If LN positive, delay chemo until 2nd trimester.
Genetic syndromes assoc with breast cancer
Autosomal dominant: Li-Fraumen (p53), Muir-Torre, BRCA1 and BRCA2, Peutz-Jeghers syndrome (hamartomatous polyps). Autosomal recessive: Ataxia-telangiectasia
Radical vs. modified vs. simple mastectomy
Radical = resect all breast tissue, axillary nodes, and pec major/minor muscles. Modified = pec muscles left intact. Simple = resection of breast tissue only
Breast cancer staging
SERM: antagonist in breast, agonist in uterus (inc risk of endometrial cancer) and bone. Used for tx of ER+ breast cancer x 10 years. Also FDA approved for prevention of breast cancer in high risk women.