Breast Physiology and Benign Diseases 5

Question 1

List the inflammatory processes of the breast.

Answer 1

• —Acute mastitis
• —Duct ectasia
• —Fat necrosis

Question 2

What is the common presentation and histology of acute mastitis. What is the most common pathogen that causes this?

Answer 2

• —Often presents as an enlarged, red, painful breast during lactation.
• —Most commonly caused by Staphylococcus aureus entering through cracks on the nipple.

Question 3

What is the histology of duct ectasia?

Answer 3

• —Often older multiparous women
• —Common presentations:
  
  • poorly defined palpable periareolar mass
  • unilateral discharge
  • nipple pain / retraction
• Dilation of ducts with periductal chronic inflammation
• —Secretions and foamy macrophages
• —Fibrosis, squamous
• Metaplasia

Question 4

What are the significant features of fat necrosis of the breast?

Answer 4

• —Usually due to trauma
• —Can be mistaken for carcinoma on imaging
  
  • —Mammogram findings:
    
    • stippled calcifications
    • —stellate contractions
  • —no increased risk of breast cancer

Question 5

What is fibrocystic change? What are the common histological findings?

Answer 5

• —Most common breast finding
• —Ages 20-50
• —Symptoms:
  
  • cyclic breast pain
  • engorgement
  • nodularity
  • —nipple discharge
• —Can also be asymptomatic and associated with mammographic findings
• Histologic categories of benign breast disease:
  
  • —Non-proliferative
  • —Epithelial Proliferations
    
    • without atypia
    • with atypia

Question 6

Why is it important to categorize the benign breast diseases?

Answer 6

• Relative risk of breast cancer depeonds on the category/type of benign breast disease
  
  • non-proliferative: relative risk similar to general population
  • proliferative without atypia: 1.5-2x relative risk fo general population
  • proliferative with atypia: 4-5x risk of general population

Question 7

List the non-proliferative breast diseases.

Answer 7

• Cysts
• Apocrine metaplasia
• Fibroadenoma

Question 8

Describe the characteristics of cysts in the breast?

Answer 8

Will drain if palpable, common finding, translucent, well-circumscribed

Question 9

Describe the important histologic features of apocrine metaplasia.

Answer 9

• —Eosinophilic finely granular cytoplasm
• —Large vesicular nuclei with prominent nucleoli
• —Apical snouts
• —Can be a single layer or form micropapillae

Question 10

Describe the important histological features of fibroadenomas.

Answer 10

• —Most common benign breast mass
• —Women <30 yo
• —Often multiple and bilateral
• —Rubbery and mobile on PE
• —Fatty breast stroma moving into fibrous ridge
• Linear and compressed look to breast epithelium, totally benign lesion
• No excision required

Question 11

List the common proliferative diseases of the breast that don’t have atypia.

Answer 11

• —Usual ductal hyperplasia
• —Sclerosing adenosis
• —Intraductal papilloma
• —Radial scar

Question 12

What are some common clinical symptoms of proliferative breast disease without atypia? What are some common histological findings?

Answer 12

• Palpable mass, may be found on screening mamography
  
  • associated with calcifications on a mammographic lesion
• Usual ductal hyperplasia is proliferation of both luminal and myoepithelial cells beyound the typical two cell layer
• Can be florid, filling and distending the involved ducts
• Hyperplastic lesions can often have streaming or spindled look with peripheral slit-like spaces and cells are often ovoid and overlapping, giving prolfierations a “jumbled” appearance

Question 13

Describe the important histologic features of sclerosing adenosis.

Answer 13

• —Lobulocentric proliferation with an increased number of acini that are compressed and distorted at the center and more dilated at the periphery
• —Involves both luminal and myoepithelial cells
• —Can have fibrosis of intralobular stroma
• —Often associated with mammographic calcifications and more rarely a mass
• Compressed acini with calcifications
• Diagnose with core biopsies

Question 14

Describe the important histological features of radial scars.

Answer 14

• Asymptomatic and non-palpable clinically
• —Stellate
• —Central nidus of entrapped glands in hyalinized and elastotic stroma
• —Dilated at the periphery with varying amount of HP, adenosis, papillomatosis
• —Can be mass forming an mimic cancer on imaging

Question 15

Describe the important histologic features of intraductal papilloomas.

Answer 15

• Present as:
  
  • bloody nipple DC
  • palpable mass
• Common between ages 30-50
• Location
  
  • solitary and central
  • multiple and peripheral
• —Microscopic:
  
  • —thick, fibrotic fibrovascular cores
  • —lined by the typical dual layer of epithelial and myoepithelial cells
  • can also contain other proliferative changes like hyperplasia
• Carcinoma in 1/3 of cases, so usually excised

Question 16

Describe the important histological features of ductal hyperplasia.

Answer 16

• —As the normal TDLU had both myoepithelial and epithelial cells, UDH is also composed of both cell types
• —If you compare to normal TDLUs in the background, the cells basically look the same (no atypia)
• Duct getting full of cells - proliferation of both the luminal and myoepithelial cells
• Florid UDH with a mixture of cells, often overlapping & jumbled with slit-like spaces
• Streaming, overlapping, oval nuclei

Question 17

List the common diseases of proliferative breast disease with atypia.

Answer 17

• —Atypical ductal hyperplasia (ADH)
• —Atypical lobular hyperplasia (ALH)

Question 18

Describe the important histological features of atypical ductal hyperplasia.

Answer 18

• —Represents about 10% of lesions of significance detected by modern breast imaging
• —Diagnosis on core biopsy prompts surgical excision as up to 20% will be upgraded to cancer
• —Most often presents as mammographic calcifications
• As opposed to jumbled, messy look, this is very orderly, monotonous, beginning neoplastic process
• All cells look round and uniform
• Can form funny ridges that are fairly unique

Question 19

Describe the important histologic factors of atypical lobular hyperplasia.

Answer 19

• —Often an incidental finding on core biopsy
• —Often a multicentric (60-80%) and bilateral (40-50%) process
• —Uniform population of small, dyscohesive cells
• —Round nuclei, indistinct nucleoli, sparse cytoplasm
  
  • can appear plasmacytoid
• —Intracytoplasmic lumens
  
  • not specific but charateristic
• Disc cohesive feeling, cells falling apart form one another
• Lost E-cadherin, so cells can’t hold together
• —Lost fat, so all single cells