SM_196: Histology and Pathology of Breast Flashcards
____ is most common site of origin of breast cancer
Upper outer is most common site of origin of breast cancer

Describe breast anatomy
Breast anatomy
- Skin and superficial fascia
- Nipple and areola
- Breast parenchyma: glandular epithelium (15-20 lobes), fibrous stroma, fibroadipose tissue

Describe histology of the nipple areolar complex
Nipple areolar complex

Breast ductal system consists of ____, ____, and ____
Breast ductal system consists of terminal duct lobular unit, breast duct, and nipple ducts

Describe basic breast histology
Basic breast histology
- White: fat
- Pink: fibrous stroma
- Purple: epithelial cells

Describe histology of breast ducts
Breast ducts

____ are the site of most breast lesions including cancer
Terminal duct lobular units are the site of most breast lesions including cancer

Younger breast has more ____ stroma on histology
Younger breast has more fibrous stroma on histology
Older breast has more ____ stroma on histology
Older breast has more fatty stroma on histology

Describe histological changes in breast during pregnancy and lactation
Pregnancy and lactation breast
- Number of lobules and acini within each lobule increase at expense of intralobular and extralobular stroma
- Luminal epithelial cells with cytoplasmic vacuoles, often protruding into lumen

Postmenopausal breast consists largely of ____
Postmenopausal breast consists largely of adipose tissue containing a few residual breast ducts and blood vessels

Inflammatory processes of breast are ___, ___, and ___
Inflammatory processes of breast are acute mastitis, duct ectasia, and fat necrosis
Fever and enlarged red painful breast mass in nursing mother (during lactation) is ___
Fever and enlarged red painful breast mass in nursing mother (during lactation) is acute mastitis
- Most commonly caused by Staphylococcus aureus entering through cracks on the nipple
Describe pathology of acute mastitis
Acute mastitis pathology
- Neutrophils (polymorphonuclear cells: acute inflammatory cells) infiltrate the breast (mast) and cause inflammation (itis)

Older multiparous women with poorly defined palpable periareolar mass, unilateral discharge, and nipple pain / retraction is ____
Older multiparous women with poorly defined palpable periareolar mass, unilateral discharge, and nipple pain / retraction is ductal ectasia
Describe pathology of ductal ectasia
Ductal ectasia pathology
- Ducts are dilated (ectasia) with chronic inflammation (mononuclear cells without multilobulation: lymphocytes and plasma cells)
- Fibrosis and squamous metaplasia

Hard breast mass, calcifications on mammogram, due to trauma is ____
Hard breast mass, calcifications on mammogram, due to trauma is fat necrosis
Describe pathology of fat necrosis
Fat necrosis pathology
- Hemorrhage and neutrophils early
- Macrophages, fibrosis, and calcifications

This is ____

This is acute mastitis

___ is the most common breast finding and includes non-proliferative and proliferative lesions
Fibrocystic changes is the most common breast finding and includes non-proliferative and proliferative lesions
- 20-50 years
- Cyclic breast pain
- Engorgement
- Nodularity
- Nipple discharge
- Can also be asymptomatic and associated with mammographic findings
____ involve the terminal duct lobular unit and are dilated ducts with inner luminal epithelial cells and outer myoepithelial cells
Simple cysts involve the terminal duct lobular unit and are dilated ducts with inner luminal epithelial cells and outer myoepithelial cells

Non-proliferative breast lesions are ____, ____, and ____
Non-proliferative breast lesions are cysts, apocrine metaplasia, and fibroadenoma
Describe pathology of apocrine metaplasia
Apocrine metaplasia pathology
- Apocrine: glands that release some of their cytoplasm in their secretions (apical snouts)
- Large polygonal cells lining ducts
- Eosinophilic (red) finely granular cytoplasm
- Small nuceli with prominent nucleoli
- Metaplasia: change in type of lining epitheliu,m

Firm, rubbery, mobile, rounded breast mass is ____
Firm, rubbery, mobile, rounded breast mass is fibroadenoma
- Most common benign neoplasm of female breast
- 20-35 years old

Mass with smooth circumscribed borders oriented parallel to skin on US is ___
Mass with smooth circumscribed borders oriented parallel to skin on US is fibroadenoma

Describe pathology of fibroadenoma
Fibroadenoma pathology
- Circumscribed mass with whorled cut surface
- Biphasic: neoplastic stroma (fibro) induces a glandular epithelial proliferation (adeno), mass forming (oma)

Fibroadenoma has ___
Fibroadenoma has well defined circumscribed border between fibroadenoma and normal fatty breast tissue

Phyllodes tumor is ___ breast lesion that presents as ____ in women aged ____
Phyllodes tumor is NOT benign breast lesion that presents as a rapidly enlarging mass in women aged 30-35 years

Describe pathology of phyllodes tumor

Phyllodes tumor pathology
- Leaf like
- Benign to sarcomatous proliferation
(requires wide margin, high recurrence rate)
This is ___

This is fibroadenoma

Describe relative risk of benign breast disease
Benign breast disease
- Non-proliferative: minimal to no increase in risk for developing breast carcinoma
- Proliferative without atypia: 1.5-2x
- Proliferative with atypia: 4-5x
Proliferative breast lesions without atypia are ____, ____, ____, and ____
Proliferative breast lesions without atypia are usual ductal hyperplasia, sclerosing adenosis, radial scar, and intraductal papilloma
Describe pathology of usual ductal hyperplasia
Usual ductal hyperplasia pathology
- Usual: cells look like cells in background terminal duct lobular units (no atypia)
- Ductal: cells that proliferate
- Hyperplasia: increase in cell number

Describe pathology of sclerosing adenosis
Sclerosing adenosis pathology
- Lobulocentric proliferation: centered around normal terminal duct lobular units
- Sclerosing: fibrosis of stroma
- Adenosis: increased number of acini

Describe pathology of radial scar
Radial scar pathology
- Radial: stellate configuration
- Scar: central nidus of small entrapped glands in hyalinized stroma
- Dilated glands at periphery with cysts or hyperplasia

Mass below nipple with bloody nipple discharge is ____
Mass below nipple with bloody nipple discharge is intraductal papilloma
Describe pathology of intraductal papilloma
Intraductal papilloma pathology
- Intraductal: involves large excretory ducts
- Papillae: fibrovascular stalks lined by both myoepithelial cells (inner) and benign epithelial cells (outer)
- Mass forming (oma)

This is ____

This is usual ductal hyperplasia

Proliferative breast lesions with atypia are ____ and ____
Proliferative breast lesions with atypia are atypical ductal hyperplasia and atypical lobular hyperplasia
Pathology of atypical ductal hyperplasia
Atypical ductal hyperplasia pathology
- Atypical: cytologic atypia (monotonous cells) and architectural atypia (Roman bridges, cribriform structures)
- Ductal: luminal epithelial proliferation
- Hyperplasia: increased number of cells

Late 40s, either breast and any quadrant, nonspecific presentation, and microcalcifications on mammography is ____
Late 40s, either breast and any quadrant, nonspecific presentation, and microcalcifications on mammography is atypical ductal hyperplasia

Incidental finding on core breast biopsy, multicentric and bilateral is ____
Incidental finding on core breast biopsy, multicentric and bilateral is atypical lobular hyperplasia
- Multicentric: involves multiple quadrants of some breast
- Bilateral: involves both breasts

Describe atypical lobular hyperplasia on pathology
Atypical lobular hyperplasia on pathology
- Lobular: uniform, small, dyscohesive cells
- Round nuclei that may be peripheral: look like plasma cells
- Intracytoplasmic lumens

One duct is partially involved by monotonous ductal epithelial cells that form punched out secondary lumens (cribriform spaces).
This is ____
Relative risk of developing breast cancer is ____

One duct is partially involved by monotonous ductal epithelial cells that form punched out secondary lumens (cribriform spaces).
This is atypical ductal hyperplasia
Relative risk of developing breast cancer is 4-5 fold

In situ carcinoma consists of ____ and ____
In situ carcinoma consists of ductal carcinoma in situ and lobular carcinoma in situ
Describe in situ carcinoma
In situ carcinoma
- In situ: in its original place or position
- Carcinoma: cancer arising from epithelial cells
- Noninvasive: has not penetrated the limiting basement membrane and remains within this normal boundary (intact outer layer of myoepithelial cells)
- Arise from terminal duct lobular unit
Relative risk of cancer is 8-10x
Ductal carcinoma in situ ___
Ductal carcinoma in situ fills and disorts duct spaces
Lobular carcinoma in situ ____
Lobular carcinoma in situ expands but does not alter acini of lobules
Ductal carcinoma is frequently associated with ____
Ductal carcinoma is frequently associated with calcifications
(secretory material or necrotic debris)
(5% in unscreened and 40% in screened populations)
Describe pathology of ductal carcinoma in situ
Ductal carcinoma in situ pathology
- Architectural patterns: solid, cribriform, papillary
- Comedo: extensive central necrosis
- Nuclear grade
- Low (bland and monotonous): cells look like each other
- High (pleimorophic cells): cells with varying sizes and shapes

Lobular carcinoma in situ is rarely associated with ___
Lobular carcinoma in situ is RARELY associated with calcifications
(incidental)
Describe pathology of lobular carcinoma in situ
Lobular carcinoma in situ pathology
- Uniform monomorphic cells with bland round nuclei in loosely cohesive clusters
- Intracellular mucin

This is ___
Treatment involves ___

This is ductal carcinoma in situ
Treatment involves surgery

Invasive breast carcinoma consists of ___ and ___
Invasive breast carcinoma consists of invasive ductal carcinoma and invasive lobular carcinoma
- Invasive: has penetrated the limiting basement membrane, spreading beyond it, and infiltrating into the stroma
- Characterized by a lack of the outer layer of myoepithelial cells: negative for myoepithelial cell makrers such as p53 and smooth muscle myosin heavy chain
- Desmoplastic stroma: pale blue-gray stroma reacting to the infiltration
Hard palpable fixed breast that comprises 70-80% of all breast cancers is ____
Hard palpable fixed breast that comprises 70-80% of all breast cancers is invasive ductal carcinoma
Describe pathology of invasive ductal carcinoma
Invasive ductal carcinoma pathology
- Well developed tubules with low grade nuclei to sheets of pleomorphic cells
- 2/3 express estrogen receptor (ER) and progesterone receptor (PR) and 1/3 overexpress HER2

____ comprise 20% of all breast cancers and 10-20% are bilateral
Invasive lobular carcinoma comprise 20% of all breast cancers and 10-20% are bilateral
Describe pathology of invasive lobular carcinoma
Invasive lobular carcinoma pathology
- Cells identical to atypical lobular hyperplasia and lobular carcinoma in situ
- Mutations in E-cadherin (surface protein that allows for normal cohesion of breast epithelium)
- Invade individually and aligned in single file strands
- Almost all epxress ER and PR, rarely overexpress HER2
- Metastasis: CSF, serosal surfaces, GI tract, ovary, uterus, bone marrow

This is ___

This is invasive ductal carcinoma
