The Breast

Acute mastitis S. aureus Breastfeeding Fever, erythema, pain Periductal mastitis – subareolar mass, smoking, keratinizing Periductal mastitis – subareolar mass, smoking, keratinizing Fibrocystic disease “LUMPY, BUMPY” dense with cysts nonproliferative

Breast Cancer Carcinoma of the breast is the most common non-skin cancer in women If lives to age 90 years 1/8 chance Main benefit of screening with mammograms is the detection of small, predominantly ER-positive invasive carcinoma and insitu carcinoma (DCIS) The major risk factors are hormonal and genetic

DCIS (calcifications on mammo) Comedocarcinoma (pleomorphic cells; microinvasion most common) Solid (monomorphic; fills spaces) Cribiform (monomorphic; cookie-cutter) Papillary (monomorphic; grows along cores no myoepithelial layer) Micropapillary (monomorphic; no core) Paget disease (erythema, crust, extend from DCIS; palpable mass in most)

Invasive (Infiltrating) Carcinoma Palpable tumors are associated with axillary lymph node metastases 50% of the time – Axillary lymph node status is the most important prognosisfactor for invasive carcinom in the absence of distant metastases Peau d’orange Inflammatory carcinoma NST (invasive ductal) – luminal A (ER+, HER2/neu -), Luminal B (triple positive), normal breast-like (ER+, HER2/neu-), basal-like (triple negative; BRCA1), HER2 positive; grating sound when cut LobularTubular/cribiformMucinous/colloidMedullaryPapillaryMetaplastic

NST Luminal A – ER+, HER2/neu – Luminal B – Triple-positive Normal breast-like – ER+, HER2/neu – Basal-like – triple negative, BRCA1 (similar to metaplastic carcinoma) HER2 positive – ER- Grate sound when cut Desmoplasia

Invasive Lobular Carcinoma Little desmoplasia, rarely palpable Dyscohesive infiltrating tumor cells, no tubules Resembles signet-ring gastric carcinoma; loss of E-cadherin Metastases to peritoneum, retroperitoneum,leptomeninges, GI tract, uterus, ovaries

MedullaryWell-circumscribed Soft, fleshy Lymph node metastases are rare overexpression of adhesion molecules BRCA1 promoter overexrpession; pushing borders Mucinous Soft, rubbery Soft, rubbery Pale blue gelatin pushing or circumscribed borders Tubular Well-formed tubules small; myoepithelial layer absent; LCIS or lobular carcinoma associated

Invasive papillary – ER positive good prognosis Invasive papillary – ER positive good prognosis Invasive micropapillary – ER negative, HER2 positive poor prognosis Invasive micropapillary – ER negative, HER2 positive poor prognosis Metaplastic carcinoma – prominent spindle, triple negative Metaplastic carcinoma – prominent spindle, triple negative

Stromal Tumors Fibroadenoma – most common benign tumor, sharply circumscribed, freely mobile (intralobular stroma; popcorn calcifications; post renal transplant treated with cyclosporin A) Phyllodes tumor- leaflike (intralobular stroma; EGFR amplification) Interlobular stromal tumors – pseudoangiomatous stromal hyperplasia, myofibroblastoma, lipoma, hamartomas, fibromatosis (gradner syndrome; B-catenin) Angiosarcoma – malignant post radiation therapy; Stewart treves syndrome (angiosarcoma from edematous extremity after mastectomy)

Male Breast Gynecomastia (puberty, elderly, cirrhosis, Klinefelter, steroids) CarcinomaKlinefelterBRCA2