Pathology of Breast Diseases Flashcards
Inflammatory disorder of the breast:
- localized
- acute inflammation
- most common cause: Staphylococcus aureus
- less common cause: Streptococcus pyogenes (GAS)
Acute mastitis
Usually cause of acute mastitis associated with suppurative inflammation that may progress to abscess (single or multiple)
Staphylococcus aureus
Usually cause of acute mastitis associated with breast cellulitis
Streptococcus pyogenes (group A streptococci)
Inflammatory disorder of the breast:
- mimics cancer clinically
- painless palpable mass
- usual history of breast trauma, manipulation, or prior surgery
- ill-defined, firm, gray-white modules containing small, chalky-white foci or dark hemorrhagic debris
- liquefactive necrosis with neutrophils, macrophages, and eventually giant cells, calcification, and hemosiderin, leading to fibrosis
Fat necrosis of the breast
Benign epithelial lesion encompassing breast cysts, fibrosis, and adenosis
Fibrocystic changes of the breast
Fibrocystic change:
- dilation of lobules
- filled with brown/blue fluid (blue-dome)
- lined with “milk of calcium” calcifications of flattened atrophic/metaplasic apocrine glands
Breast cyst
Fibrocystic change:
- caused by cyst rupture, inducing inflammation
Breast fibrosis
Fibrocystic change:
- increased number of acini per lobule
- columnar cell lining with flattened epithelial atypia
Breast adenosis
Benign epithelial lesion encompassing epithelial hyperplasia (typical/usual ductal hyperplasia), sclerosing adenosis, complex sclerosis, papillomas, atypical ductal hyperplasia, and atypical lobular hyperplasia
Proliferative breast lesions without atypia
Proliferative breast lesions without atypia:
- > 2 layers of myoepithelial cells and luminal cells (usually 1 layer each) - heterogenous cells
- irregular, peripheral, slit-like lumen
- mimics ductal carcinoma-in-situ (DCIS)
Epithelial hyperplasia or typical/usual ductal hyperplasia
Proliferative breast lesions without atypia:
- acini more than doubled at the uninvolved lobules
- compression at the center due to surrounding fibrosis (solid cords or double-strands of cells in densely fibrotic stroma)
- mimics breast carcinoma
Sclerosing adenosis
Proliferative breast lesions without atypia:
- papillary fronds with fibrovascular core growing within a dilated duct
- bloody nipple discharge - most common cause in women younger than 50 (when intraductal)
- develops on the lactiferous ducts or sinuses
- no known risk for cancer
Breast papilloma
Proliferative breast lesions without atypia:
- COMBINATION of components of epithelial cell hyperplasia, sclerosing adenosis, and papilloma
- central nidus of entrapped glands
- radiating projections of glands and stroma, with radial sclerosing lesion (radial scar)
- mimics breast cancer
Complex sclerosis or complex sclerosis breast lesion
Proliferative breast lesions without atypia:
- monomorphic cells - ductal cells only
- round, rigid lumina = cribriform/cookie-cutter appearance
- resembles DCIS but with limited (< 2mm) duct involvement
- loss of 16p and gain of 17q (also in ALH nad CIS)
Atypical ductal hyperplasia (ADH)
Proliferative breast lesions without atypia:
- monomorphic round cells - lobular only - loosely cohesive (similar to LCIS and ILC), due to loss of E-cadherin
- resembles LCIS but with limited (< 50%) involvement if acini per lobule
- loss of 16p and gain of 17q (also in ADH nad CIS)
Atypical lobular hyperplasia (ALH)
Most common cancer in the adult woman, with a mean age of 64 years old; also the 2nd most common cancer producing death in women (followed by lung cancer)
Breast carcinoma
Benign epithelial change with the most relative risk for break cancer development
Carcinoma-in-situ (CIS)
(Relative risks:
- fibrocystic changes = 1.0 or 3%
- proliferative disease without atypia = 1.5-2.0 or 5-7%
- proliferative disease with atypia = 4.0-5.0 or 13-17%
- carcinoma-in-situ = 8.0-10.0 or 25-30%)
Type of carcinoma-in-situ:
- intact basement membrane
- disrupted lobules
- may have papillary/cribriform patterns
- necrotic with secretory activity; thus, with calcification
- divided into comedo and non-comedo types
- Paget disease of the nipple observed
- 10-20% bilateral
- variable hormonal status (usually ER-negative and HER2-positive if with Paget disease of the nipple)
Ductal carcinoma-in-situ (DCIS)