#69 – Benign Breast Diseases


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

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


  • 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


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


  • 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



  • 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


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



  • 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


  • 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

1893 Cottage Physician


  1. https://armandoh.org/disease/breast-cancer/
  2. Schnitt SJ. Benign breast disease and breast cancer risk: morphology and beyond. Am J Surg Pathol. 2003; 27(6):836-41. [pubmed]
  3. Hartmann LC, Sellers TA, Frost MH, et al. Benign breast disease and the risk of breast cancer. N Engl J Med. 2005; 353(3):229-37. [pubmed]
  4. Guray M, Sahin AA. Benign breast diseases: classification, diagnosis, and management. Oncologist. 2006; 11(5):435-49. [pubmed]
  5. Breast Disease. In: Hoffman BL, Schorge JO, Halvorson LM, Hamid CA, Corton MM, Schaffer JI. eds. Williams Gynecology, 4e. McGraw-Hill; Accessed February 21, 2021. https://accessmedicine-mhmedical-com.ezproxy.uthsc.edu/content.aspx?bookid=2658&sectionid=218608871
  6. Giuliano AE, Hurvitz SA. Breast Disorders. In: Doherty GM. eds. Current Diagnosis & Treatment: Surgery, 15e. McGraw-Hill; Accessed February 21, 2021. https://accessmedicine-mhmedical-com.ezproxy.uthsc.edu/content.aspx?bookid=2859&sectionid=242155824
  7. Littrup PJ, Freeman-Gibb L, Andea A, et al. Cryotherapy for breast fibroadenomas. Radiology. 2005; 234(1):63-72. [pubmed]
  8. Linda A, Zuiani C, Furlan A, et al. Radial scars without atypia diagnosed at imaging-guided needle biopsy: how often is associated malignancy found at subsequent surgical excision, and do mammography and sonography predict which lesions are malignant? AJR Am J Roentgenol. 2010; 194(4):1146-51. [pubmed]
  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]

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