3. Robbins Breast Pathology Flashcards
What is the functional unit of the breast and where many breast cancers arise?
Terminal duct lobular unit = lobule + duct
Describe the TDLU.
- In each lobe, lactiferous duct branches repeatedly, forming many terminal ducts, each connecting to a LOBULE, which contains many acini that makes milk (TERMINAL DUCT + LOBULE = TDLU)
- Terminal duct can be broken down into:
- Intralobular terminal duct: within the duct, intralobular ducts carry milk from acini (functional unit of the breasts) => extralobular terminal duct for each lobule
- Extralobular terminal duct: attaches to the lobule
Describe breast epithelium.
Lines surface of ducts and lobules.
Contains 2 layers of epithelium, over BM.
- Luminal columnar epithelial cells: innermost layer that secretes milk
- Myoepthielial cells: outermost layer that are contractile and respond to oxytocin.
Breast stroma
2 different kinds
1. Intralobular stroma: surrounds acini and hormonally responsive fibroblast-like cells
2. Interlobular stroma: dense fibrous CT and fat
What 6 lesions can arise in the lobules and terminal ducts of the breast?
- Cysts
- Sclerosing adenosis
- Small duct papilloma
- Hyperplasia
- Atypical Hyperplasia
- Carcinoma
What are developmental disorders of the breasts?
- 1. Milk line remnants
- 2. Acessory axillary breast tissue
- 3. Congenital nipple inversion
What are milk line remnants and how do they most commonly come to attention clinically?
- Breast tissue develops from embryonic structures called milk lines, two epidermal thickenings that form the breast and nipples.
- Milk lines run from axilla => groin and form usually dissppear in development, except in breasts. Persistance of epidermal thickenings (milk line remnants) along the milk lines that form a 3rd nipple or breast (supernumerary nipples/breasts called polythelia/polymastia), usually below NL breasts.
- Present as painful PRE-menstrual enlargements
What is accessory axillary breast tissue?
NL ductual tissue extends to the subQ tissue of the chest wall or axilla.
What are clinical presentation of breast disease?
- Pain (mastalgia/masodynia): cyclic with period or noncylic: almost all painful masses are benign but 10% of breast cancers are painful
- Palpable mass
- Nipple discarge
Causes of:
- Cyclic breast pain
- Noncyclic breast pain
- Cyclic; often diffuse and due to premenstrual edema
- Noncyclic; often localized and due to ruptured cyst, injury, infection.
What is the clinical significance of accessory axillary breast tissue; managed how clinically?
- Malignancy and other lesions can occur
- Prophylactic mastectomies ↓ risk, but do NOT completely eliminate
Why is acquired nipple inversion of greater concern than congenital?
Can indicate invasive cancer or an inflammatory nipple disease
Palpable masses of the breast are most commonly due to what 3 etiologies?
- Cysts
- Fibroadenomas
- Invasive carcinoma
Are most palpable masses benign or malignant?
- Benign in premenopausal women, but ↑ chance of malignancy with ↑ age: 60% > 50YO.
Why does screening for palpable masses have LITTLE effect on mortality?
Once a palpable mass is felt, the cancer is often metasized.
In what setting is nipple discharge most worrisome that it is cancer?
Spontaneous, unilateral and >60YO
In what situations do we most often see the following types of discharge:
1. Milky (galactorrhea)
2. Bloody or serous
- ↑ prolactin, hypothyroidism, endocrine anovulatory syndromes and meds (OC, TCA, methyldopa, phenothiazines)
-
Cysts or large duct (intraductal) papillomas;
- blood = pregnancy
Where are benign breast masses and malignant breast cancers most common on the breast?
- Benign: anywhere
- Malignant breast cancer: Upper outer quadrant (50%) bc has most breast tissue > Subareolar/central region (20%)
- ______\_ lesions are more common in premenopausal women
- _______ lesions are more common in post-menopausal women (corollary ^^)
- Only ____ of cancer are detected as a palpable mass. How are the others detected?
- Benign => premenopausal
- Malignant => post-menopausal
- 1/3; mammogram
- What are the the principal signs of breast cancer on mammograms, the most common way to detect breast cancer?
- Densities
- Calcifications
What characteristics of a density detected on mammogram is associated with benign vs. malignant lesions?
- Benign fibroadenoma or cyst = rounded densities
- Malignant = irregular masses
On mammogram:
Benign calcifications are usually due to:
Malignant calfications (ductal carcinoma in-situ) are described as:
- Benign: clusters of apocrine cysts, hyalinized fibroadenomas and sclerosing adenosis
- Malignant: small, irregular, numerous and clustered
- Screening with mammograms has increased the diagnosis of _____________.
- After mammogram, perform ____.
- DCIS (ductal carcinoma in-situ), because it is most often detected by calcifications
- Biopsy
Breast inflammation (mastitis) is RARE except during ________ and occurs due to what?
- Lactation
- Infections, AI disease and FB reactions to leaked keratin or secretions.
What can mimic inflammation of the breast?
Inflammatory breast cancer bc it can obstruct dermal vasculature with tumor emboli
What are the types of inflammatory breast disorders?
- Acute mastitis
- Squamous metaplasia of lactiferous ducts
- Ductal ectasia
- Fat necrosis
- Lymphocytic mastopathy (diabetic mastopathy)
- Granulomatous mastitis
KEY WORDS:
- Mastitis
- Mammary Duct Ectasia
- Fat Necrosis
- Mastitis: erythema and tender
- Mammary Duct Ectasia: white discharge
- Fat Necrosis: due to trauma
What is acute bacterial mastitis?
Symptoms?
Tx?
- During the 1st month of breastfeeding, sucking can cause trauma (cracks and fissures) of the nipple, making it vulnerable to bacteria, particulary S. aureus.
- Breast is red, painful +/- fever
- Tx: ABX, continue breastfeeding; rarely perform surgical drainage
What is Squamous Metaplasia of Lactiferous Ducts (also called what)?
Periductal mastitis; Recurrent subareolar abscess, and Zuska disease.
- Inflammation of the subaerolar ducts seen in smokers, that forms a painful, red subaerolar mass with nipple retraction
What symptoms is commonly seen in Squamous Metaplasia of Lactiferous Ducts?
Inverted nipples
Risk factors for squamous metaplsia of lactiferous ducts (aka recurrent subareolar abscess, periductal mastitis, and Zuska):
- Tobacco smoke
- Relative vitamin A deficiency
Key morphological features of squamous metaplasia of lactiferous ducts (aka recurrent subareolar abscess, periductal mastitis, and Zuska)?
-
Squamous metaplasia of lactiferous duct: Cuboidal epithelium => keratinzed squamous epithelium
- => Keratin is shed and plugs ducts
- => Ducts rupture and dilate
- => Intense chronic granuloma inflammation
- => fibrosis => myofibroblasts contracts => invert nipple
Treatment for Squamous Metaplasia of Lactiferous Ducts
- Simple incision drains abcesses; but can recur is keratinized epithelium stays
- En block surgical removal of duct and fistula cures
What is duct ectasia?
What is it caused by?
- Benign chronic Inflammation and fibrosis of the subareolar duct => dilation due to build up of inflammatory debris=> irregular, palpable periareolar breast mass (painLESS and NOT red) below the nipple + white discharge
Clinical case of duct ectasia?
MC in who?
Older W (50-60 YO) with many children (multiparous) presents to the clinic with breast mass right below nipple with thick, white disharge.
In duct ectasia, the ectatic ducts are filled with what?
- Inspissated secretions
- Lipid-laden MO
What is the PRINCIPAL SIGNIFICANCE of ductal ectasia worrisome?
Mimics invasive carcinoma clinically and on imaging because it is more common in POST-menopausal women
What is fat necrosis of the breast?
Necrosis of breast fat, usually due to trauma or hx of prior surgery that causes benign inflammatory process that forms a [painless, palpable mass with thick skin/retraction] and form calcifications/densities.
What inflammatory cells do we see in fat necrosis of the breast in acute vs chronic?
- Acute = MO and neutrophils;
- Chronic= fibroblasts and inflamm cells form giant cells, calficiation and deposition of hemosiderin, forming scar tissue.
What are lymphocytic mastopathy (aka: ____________)?
Sclerosing lymphocytic lobulitis/ diabetic mastopathy
-
Single or multiple rock hard masses that on histology, show:
- Atrophic ducts surrounded by collagenized stroma
- Thick BM, surrounded by lympocytes
Lymphocytic mastopathy most commonly occurs in patients who have what?
- T1DM
- Autoimmune thyroid diseases
suggesting it is AI
How are benign epithlial breast lesions categorized?
Risk of development into breast cancer
- Non-proliferative breast changes/fibrocytic: all benign; no increase risk in BC
- Proliferative breast changes, without atypia: SMALL increase risk in BC
- Atypical hyperplasia: moderate increase risk of cancer bc has SOME, but not all features to dx as CIS
3 types of nonproliferative breast changes (fibrocystic change),
- Cysts, often with apocrine metaplasia
- Fibrosis
- Adenosis
- Non-proliferative breast changes (fibrocystic change) are a group of morphological fibrocystic changes of the breasts that are all benign => no risk of breast cancer (non-proliferative) that lead to ___________ most commonly in ________
lumpy-bumpy breasts in pre-menopausal women
Describe the non-proliferative breast changes
- Simple Cysts: Fluid filled, round cysts that contain dark fluid: turbid, semi-translucent brown-blue fluid (blue domed cyst) formed by the dilation of lobules and lined with [flat, atrophic epithelium] or [metaplastic apocrine cells]
- Fibrosis: Occurs when a cysts ruptures and releases secretory material into the => fibrosis, creating lumpy bumpy breasts
- Adenosis: ↑ # of acini/lobule that occurs normally during pregnancy
Diagnosis of Simple Cysts
Fine needle aspiration of cysts causes it to disappear
Adenosis,↑ in the number of acini per lobule, may show what histological change that is thought to be the earliest recognizable precursor of low-grade cancer, even though there is NO increase risk of breast cancer.
“Flat epithelial atypia” of columnar cells due to a Chr16q deletion.
Proliferative breast disease without atypia is characterized by what; what is the association with carcinoma?
- Proliferations of epithelial cells without atypia, causing only a SMALL ↑ risk of breast cancer, but NOT true precursors to cancer
4 types of Proliferative Breast Disease without Atypia
- Epithelial hyperplasia
- Sclerosing adenosis
- Complex Sclerosing Lesion
- Intraductal papilloma
What is Epithelial Hyperplasia?
- ↑ # of luminal and myoepithelial cell, which fill & distend ducts and lobules usually found incidentally.
What is Sclerosing Adenosis?
- ↑ # of acini/glands and dense fibrosis in central part of the lesion => dense stroma compresses the glands
- Often could undergo calcification.
What are complex sclerosing lesions?
Lesions that have compenents of
- sclerosing adenosis
- papilloma
- epithelial hyperplasia.
Which lesions of proliferative breast disease without atypia has an irregular shape and can mimic invasive carcinoma mammographically, grossly, and histologically?
Complex sclerosis lesion => radial sclerosis lesion (aka radial scar)
When do cysts cause concern?
When solitary and firm
Describe a radial sclerosing lesion.
- Central area of entrapped glands in hyalinized stroma surrounded by long, radiating projections into stroma
Describe intraductal papillomas.
Fibrovascular projections lined with epithelial cells (both kinds) that extend inside of ducts (intraductal) that cause blood/serous discharge MC in premenopausal women
80% of papillomas present with bloody/serous discharge.
What is frequently seen with papillomas
epithelial hyperplasia & apocrine metaplasia (NOT a pre-cursor to cancer)
What is the ONLY benign lesion seen in the male breast?
Gynecomastia caused by androgen/estrogen imbalance.
What do we see physically in gynocomastia?
Associated with a increase risk of cancer?
- Unilateral or bilateral buttonlike subareolar enlargement that is associated with a SMALL increase risk of breast cancer.
What is the seen histologically in gynecomastia?
- ↑ in dense collagen CT
- + epithelial hyperplasia of ducts
- + tapering micropapillae (NO lobule formation)
- No lobules form
What are some of the underlying risk factors for gynecomastia?
- Cirrhosis–> liver is not metabolizing estrogen
- Drugs –> alcohol, marijuana, heroin, antiretroviral’s, and anabolic steroids
- Puberty
- Klinefelters (M 47 XXY; male hypogonadism => decrease testosterone)
Is gynecomastia associated with an increased risk for cancer?
Yes, small ↑ risk due to being proliferative breast disease without atypia
2 types of Proliferative Breast Diseases with Atypia
- Atypical ductal hyperplasia
- Atypical lobular hyperplasia
What is proliferative breast diseases with atypia?
Atypical hyperplasia that has with some, but not all, histological features of ductal carcinoma in situ (DCIS)
What is the difference between atypical ductal hyperplasia and atypical lobular hyperplasia?
-
Atypical ductal hyperplasia (ADH): histologically looks like DCIS (ductal carcinoma in-situ), but duct is PARTIALLY FILLED* with different cells:
- Periphery = oriented columnar cells
- Center = round cells.
- Some spaces are round and peripheral spaces have slits.
- Atypical lobular hyperplasia (ALH): histologically identical to LCIS: lobules are filled with discohesive cell growth (loose intercellular connections) dt lose of E-cadherin => cells become round/clump together, but do NOT take up more than 50% of lobule acini
What genetic abnormalities do we see in BOTH ADH and ALH?
- Loss of Chr 16q
- Gain of Chr 17p
- *** Both also seen in CIS
Which genetic feature of atypical lobular hyperplasia (ALH) is shared with lobular CIS?
- Loss of E-cadherin
What is seen on biopsy of fat necrosis in the breast in both acute and chronic settings?
- Acute = liquefactive fat necrosis w/ neutrophils and MO
- Chronic = giant cells + calcifications and hemosiderin => scar tissue
What is the most common non-skin malignancy in females?
Breast cancer
- 2nd leading cause of cancer deaths in women, after lung cancer
_____ of women in the US will get breast cancer by 90 YO
12.4% or 1/8