Flashcards in Breast Pathology Deck (13)
How many layers of epithelium line breast lobules and ducts? What are they?
- 2 layers!
- the inner luminal cell layer (protective)
- the outer myoepithelial cell layer (contractile)
What are the four major inflammatory conditions of the breast? What characterizes each? Which can present as masses?
- acute mastitis: bacterial infection (MCC: S. aureus) associated with breast feeding; can form an abscess
- periductal mastitis: subareolar inflammation with nipple retraction; seen in smokers with vitamin A deficiency; MASS
- mammary duct ectasia: inflammation and dilation (ectasia) of subareolar ducts; classic green-brown nipple discharge; biopsy shows inflammation with plasma cells (AKA plasma cell mastitis); MASS
- fat necrosis: trauma; presents as a MASS or as a mammogram calcification (due to saponification)
What is the most common cause of breast lumps in premenopausal women? How does it present? Is there an increased risk of cancer?
- MCC of breast lumps in premenopausal women older than 35 is fibrocystic changes (fibrosis and cyst formation)
- presents with breast tenderness and lumps, often bilateral and multifocal
- cysts have a characteristic blue-domed appearance and are fluid-filled
- generally, no increased risk of cancer
What is sclerosing adenosis? What about epithelial hyperplasia? Do these increase the risk of cancer?
- sclerosing adenosis: intralobular and luminal fibrosis and proliferation that is associated with calcifications (mimics carcinoma); 2x increased risk for developing cancer
- epithelial hyperplasia: hyperplasia of terminal ductal or lobular epithelium (presence of more than 2 epithelial layers); if cells are atypical, there is a 5x increased risk for cancer
What are the three main types of benign breast tumors? What characterizes each? Which have an increased risk of developing invasive carcinoma?
- fibroadenoma: the MC benign breast tumor (peak incidence is 30); small well-defined mobile mass; estrogen sensitive (size and tenderness increase in pergnancy and prior to menstruation); no increase risk for invasive carcinoma
- intraductal papilloma: finger-like projection growing within a lactiferous duct; this is the MCC of nipple discharge (serous or bloody); 2x increased risk
- phyllodes tumor: large bulky mass with leaf-like projections; some may be malignant
When do malignant breast cancers usually arise? What are the risk factors?
- most arise postmenopause (vs most benign breast tumors arise premenopause)
- RFs: increased estrogen exposure (female, age, early menarche/late menopause, obesity, nulliparity), BRCA1 and BRCA2, alcohol, poor diet
- black and Hispanic patients have increased risk of developing triple negative cancers at an earlier age
What is DCIS? How is it usually detected? How about LCIS?
- these are noninvasive malignancies
- DCIS: proliferation of ductal cells that fills the lumen; no BM penetration; often detected as calcifications on mammogram (masses are rare)
- LCIS: malignant proliferation of lobule cells; no BM penetration; incidental finding as both calcifications and masses are rare (a patient with LCIS is at an increased risk of developing cancer in either breast; the LCIS isn't really an in-situ cancer)
What is comedocarcinoma? What about Paget disease? What characteristic findings are associated with each?
- comedocarcinoma is a subtype of DCIS; high grade cells with central caseous necrosis
- Paget disease develops once DCIS progresses down the lactiferous duct and involves the nipple; eczematous patches on the nipple develop; (Paget cells are large intraepithelial adenocarcinoma cells with clear halos)
What is IDC? How common is it and how does it present?
- invasive ductal carcinoma is the MC type of invasive carcinoma (75%)
- glandular, duct-like cells (vs. ILC, where ducts are not seen)
- IDC presents as a mass; advanced disease can involve nipple retraction/dimpling
- it is highly invasive and has a poor prognosis
- (2/3 express estrogen or progesterone receptors, 1/3 overexposes HER2/NEU)
What is ILC? How does it present? How are these malignant cells classically arranged on biopsy? What causes this formation?
- invasive lobular carcinoma
- is often bilateral and multifocal
- cells are arranged in a straight line ("Indian file") due to the loss of E-cadherin
- (nearly all express estrogen or progesterone receptors, but HER2/NEU over expression is rare)
What is medullary carcinoma? What about inflammatory breast cancer? What is the prognosis for each?
- medullary carcinoma: characterized by lymphocytic infiltrate; associated with BRCA1; good prognosis despite often being triple negative
- inflammatory breast cancer: develops via dermal lymphatic invasion/blockage by breast cancer; breast is highly erythematous and swollen with a peau d'orange appearance (commonly mistaken for mastitis and Paget disease); poor prognosis (50% 5-year survival)
What percent of breast cancers are due to inherited mutations? Which genes are responsible and which chromosomes are they found on? What type of genes are they?
- 10% are inherited
- BRCA1: chromosome 17 (also ovarian, prostate)
- BRCA 2: chromosome 13 (also ovarian, prostate, male breast, pancreas)
- both are DNA repair genes
- (both also greatly increase the risk for developing ovarian cancer)