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***LISTEN TO THE PODCAST HERE***

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Anatomy and Physiology

• Primary components of the breast are terminal duct lobular ubnits, lobular stroma, interlobular stroma, ducts, and lactiferous sinuses
  • Epithelium (terminal duct lobular units) is the most hormonally responsive
• Natural hormonal changes of puberty, pregnancy, lactation, and menopause can lead to remodeling of these structures

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Main Classifications

• There are four main classifications of benign breast disorders that are based on the degree of cellular proliferations and atypia present
  • Nonproliferative
    • Characterized by acinar dilation and fibrosis
    • Generally, not associated with increased risk of cancer
  • Proliferative without atypia
    • Characterized by accumulation of luminal epithelial cells
    • Small increased risk of cancer (1.5-2x general population)
  • Atypical hyperplasia
    • Change in size, shape, or nuclear function of epithelial cells
    • High risk of cancer development
  • Miscellaneous

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Epidemiology

• 50% of women will experience a non-cancerous breast mass at some point in their lives
• Age of diagnosis
  • Mean age of 51 years
    • Younger in proliferative
    • Older in atypical
• Family History
  • Strongest in patients with atypical

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NONPROLIFERATIVE DISORDERS

Breast Cysts

• Most common
  • 25% of nonproliferative
  • 35-50 year olds
• Fluid-filled, round mass originating from the terminal duct lobular unity
• Patient Presentation
  • Painful or painless
  • Often solitary
• Physical Examination
  • Smooth and firm to palpation with distinct border
• Diagnostic Studies
  • Ultrasound
    • Simple
      • Anechoic throughout with posterior acoustic enhancement
    • Complicated
      • Homogenous low-level internal echoes with debris, thick walls, or thick septa
        • No solid components
    • Complex
      • Fluid and solid components without posterior wall enhancements

• Management
  • Simple – no intervention required
  • Complicated – repeat imaging in 6 months
  • Complex – biopsy or FNA

Galactocele

• Milk retention cysts usually caused by obstructed milk ducts
• Physical Examination
  • Soft, cystic mass
• Diagnostic Studies
  • Ultrasound
    • Complex echogenicity

• Management
  • FNA reveals milky substance
  • No further intervention required

Hyperplasia of Usual Type

• Increase in the number of epithelial cells within a duct that is more than two, but not more than four cells in depth and do not cross the lumen of the involved space

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PROLIFERATIVE DISORDERS WITHOUT ATYPIA

Fibroadenoma

• Most common benign tumor of the breast
  • 50% of all breast biopsies
  • 20% have multiple
• Most common in younger women
  • 15-35 years of age
• Likely hormonally driven
  • Persist through reproductive year’s, increase during pregnancy or with estrogen therapies, and decrease after menopause
• Physical Examination
  • Well-defined, mobile mass on palpation
• Diagnostic Studies
  • Ultrasound
    • Well-defined solid mass with isoechogenicity

• Management
  • Biopsy is indicated to further stratify
    • Simple
      • Contains glandular and fibrous tissue
      • Watch vs excision vs cryoablation
        • If any change during observation, then excision is warranted
    • Complex
      • Contains duct epithelial hyperplasia or calcification
      • Observation vs excision

Intraductal Papilloma

• Papillary cells that grown from the wall of a cyst into its lumen
• Can hide areas of atypia or ductal carcinoma in situ
• Two types
  • Solitary
    • Solid mass on examination or incidental imaging
    • Nipple discharge is common presenting sign
  • Multiple
    • Minimum of five papillomas within a localized segment of tissue
• Diagnostic Studies
  • Often found on routine mammography, but ultrasound is recommended if there is a palpable mass
    • Will show a mass within a cystic space

• Management
  • Solitary
    • Biopsy and excision if atypical cells present
  • Multiple
    • Excision of breast segment

Sclerosing Adenosis

• Lobular lesions with increased fibrous tissue and interspersed glandular cells
• Found on routine mammography
  • Architectural distortion with irregular borders and microcalcifications
• No interventions needed outside of routine imaging

Radial Scar

• Complex sclerosing lesions found on routine imaging AFTER biopsies or excisions have been performed
• Pathologic by definition due to appearance
• Diagnostic Studies
  • Mammography often shows low-intensity, spiculated masses that are indistinguishable from spiculated carcinomas

• Management
  • Biopsy reveals fibroelastic cores with radiating ducts and lobules
  • Excision is recommended (though controversial) and is often definitive

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PROLIFERATIVE LESIONS WITH ATYPIA

Atypical Ductal Hyperplasia (ADH)

• Characterized by proliferation of uniform epithelial cells with monomorphic round nuclei filling the involved duct
  • Must be < 2mm or involving < 2 ducts
• Can share cytologic and morphologic features of low-grade ductal carcinoma in-situ
• Diagnosed by core needle biopsy
• Management
  • Excisional breast biopsy with good margins

Atypical Lobular Hyperplasia (ALH)

• Characterized by proliferation of monomorphic, evenly spaced, dyshesive cells filling the involved lobule
  • Generally found on incidental biopsy for other clinical reason
• Can share cytologic and morphologic features of low-grade lobular carcinoma in-situ
• Diagnosed by core needle biopsy
• Management
  • Excisional breast biopsy with good margins

Lobular Carcinoma in-situ

• Invasive lesion that arises from the lobules and terminal ducts of the breast
• 80-90% of cases diagnosed in premenopausal women with a mean age of 45 year’s
• Strong estrogen receptor positivity
• Diagnosed by core needle biopsy on other incidental reason
  • LCIS is generally not diagnosed clinically, radiographically, or by gross pathologic examination
• Three types
  • Classic
    • Solid proliferation of small cells with small, uniform round nuclei and variably distinct cell borders with cytologic dyshesion
    • Clear to lightly eosinophilic cytoplasm with possible signet ring cells and vacuoles
  • Pleomorphic
    • Larger cells with marked nuclear pleomorphism
  • Florid
    • Marked distension of the involved ducts and lobules that become mass-forming
    • Central necrosis with calcifications
• Management
  • Excisional breast biopsy

Flat Epithelial Atypia

• Characterized by neoplastic alteration of the terminal duct lobular units with replacement of the native epithelial cells with columnar cells
• Diagnosed by core needle biopsy after mammographic evidence of microcalcifications
• Management
  • Excisional breast biopsy

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MISCELLANEOUS

Lipoma

• Solitary mature fat tumors of the breast that do not contain histologic evidence of breast tissue
• Physical Examination
  • Soft, non-tender, well-circumscribed mass
    • Difficulty to clinically differentiate from other conditions
• Excisional biopsy is preferred

Fat Necrosis

• Occurs as a result of breast trauma or surgical intervention
• Can be confused with malignancy both clinically and radiographically
  • May see oil cysts on mammography or ultrasound
• Biopsy is often needed to diagnose, but no further treatment is indicated

Diabetic Mastopathy

• Seen in premenopausal women with long standing type 1 diabetes mellitus
• Mammogram shows dense pattern
• Diagnosed by core needle biopsy
  • Shows dense, keloid-like fibrosis with periductal, lobular, or perivascular lymphocytic infiltration
• No further treatment after diagnosis

Hamartoma

• Lesions containing varying amounts of glandular, adipose, or fibrous tissue
• Present as discrete, encapsulated, painless masses found on incidental radiographic screening
• FNA or CNB are not sufficient to make the diagnosis and excisional biopsy is preferred

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1893 Cottage Physician

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References

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9. American Society of Breast Surgeons. Official statement. Consensus guideline on concordance assessment of image-guided breast biopsies and management of borderline or high-risk lesions. 2016. Available at: https://www.breastsurgeons.org/docs/statements/Consensus-Guideline-on-Concordance-Assessment-of-Image-Guided-Breast-Biopsies.pdf
10. Guray M, Sahin AA. Benign breast diseases: classification, diagnosis, and management. Oncologist. 2006; 11(5):435-49. [pubmed]