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Benign breast conditions

Last updated: August 6, 2021

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There are a number of benign conditions that can affect the breasts, including congenital anomalies (e.g., supernumerary nipples), fat necrosis, mastitis, fibrocystic changes, gynecomastia, mammary ductal ectasia, and neoplasms such as fibroadenoma, phyllodes tumor, and intraductal papilloma. Fibrocystic changes result in the most common benign lesion of the breast, and, like the rest of these lesions, primarily affect women between the third and fifth decades of life. Although benign breast conditions may cause symptoms that mimic breast cancer, the majority of these lesions do not increase the risk of malignant disease. They are usually diagnosed with ultrasound and mammogram, but in some cases biopsy is required. Because of the benign character of these conditions, treatment does not generally involve surgery.

Overview of benign breast conditions
Disorder Epidemiology [1] Clinical features Diagnostics Treatment
Congenital anomalies of the breast
  • Affect 1–6% of the general population [2]
  • Clinical
  • Surgical correction
Fibrocystic changes
  • Most common benign lesion of the breast
  • Premenstrual breast tenderness
  • Multiple breast nodules bilaterally
  • Most common in nursing mothers
  • Clinical
Fat necrosis
  • Unnecessary
  • Most common benign breast lesion in lactating women
  • Frequently occurs during or after lactation
  • Painless, firm mass
  • Repeated needle aspiration or surgical excision if cysts are symptomatic


  • Firm, concentric mass at the nipple-areolar complex, which may be tender
  • Mainly clinical
  • Mammogram (in ambiguous cases)
  • Only required in persistent cases
  • Medical therapy: testosterone replacement or tamoxifen
  • Surgery (subcutaneous mastectomy)
  • Treatment of the underlying cause
  • Most common breast mass in women < 35 years
  • Solitary, well-defined, non-tender, rubbery, and mobile mass
  • Regular check-ups
Phyllodes tumor
  • Painless, smooth, multinodular lump
  • Variable growth rate
  • Generally > 3 cm
  • Surgical excision
Intraductal papilloma
  • Peak incidence
    • Solitary lesions: ∼ 48 years
    • Multiple lesions: ∼ 41 years
  • Surgical excision
Mammary duct ectasia
  • Usually unnecessary
  • Antibiotic therapy if infected
  • Surgical excision for persistent lesions

The mammary ridge regresses in the 7th–8th week of embryonal development. Disorders during this stage of development may lead to the following anomalies:

  • Amastia: absence of breast tissue and nipples
  • Polymastia: presence of accessory breast tissue
  • Athelia: absence of nipples
  • Polythelia: presence of accessory nipples
  • Poland syndrome [3]
    • Unilateral aplasia/hypoplasia of the pectoralis muscles and breast with associated fingers abnormalities (e.g., brachysyndactyly)
    • Most commonly develops on the right side


  • Definition: benign changes characterized by the formation of fibrotic and/or cystic tissue [4][5]
  • Epidemiology
    • Most common benign lesion of the breast
    • Primarily in premenopausal women 20–50 years of age
    • Up to 50% of women are affected during their lifetime.
  • Etiology: unknown

Histologic subtypes [6]

Clinical features

Diagnostics [8]

  • Physical exam
  • Ultrasound and mammogram (first-line)
    • Ultrasound
      • Findings range from normal appearance to focal regions of thick parenchyma.
      • Сysts may be present.
    • Mammogram (not recommended for women < 30 years)
      • Round or oval masses with clear borders
      • In some cases, dispersed calcifications
  • Fine-needle aspiration (after imaging confirms a cystic lesion): indicated if the patient is symptomatic and/or requests the procedure
  • Biopsy: confirms diagnosis if imaging is inconclusive

Treatment [9]


Depends on the histologic subtype:

  • Nonproliferative lesions do not increase the risk of cancer.
  • Proliferative lesions with atypical cells (e.g., ductal epithelial hyperplasia) are associated with an increased risk of cancer.

Patients with mastitis should continue breastfeeding to reduce the risk of a breast abscess.

Breast abscess [15]

A fluctuant mass may indicate a breast abscess.

  • Definition: subareolar periductal chronic inflammatory condition defined by dilated mammary ducts which are eventually clogged [19]
  • Epidemiology
  • Etiology: inspissated luminal secretion stasis leading to periductal inflammation and fibrous obliteration
  • Clinical features
  • Diagnostics
  • Treatment
    • Usually not necessary (most cases resolve spontaneously)
    • Antibiotic therapy if infected
    • Surgical excision for persistent lesions

Mammary duct ectasia is the most common cause of greenish nipple discharge.


Phyllodes tumor [24]

Intraductal papilloma

  • Definition: solitary or multiple benign lesions that arise from the epithelium of the lactiferous breast ducts [25]
  • Epidemiology: peak incidence: 40–50 years
    • Multiple lesions: ∼ 41 years
    • Solitary lesions: ∼ 48 years
  • Etiology: unknown
  • Clinical features [26]
    • Solitary lesions (also known as central papilloma)
    • Multiple lesions (also known as peripheral papilloma)
      • Usually asymptomatic but may cause nipple discharge in rare cases
      • Peripheral lesions
      • Smaller compared to solitary lesions
  • Diagnostics
  • Treatment: surgical excision of the affected duct
  • Prognosis
    • Generally excellent; for most lesions, there is no risk of malignant transformation
    • Lesions with atypical hyperplasia are associated with an increased risk of breast cancer

Intraductal papilloma is the most common cause of bloody nipple discharge.

Lobular carcinoma in situ (LCIS) [28]

  • Characteristics
    • Microcalcifications or production of a mass are rare (usually incidental biopsy finding).
    • Lower risk of subsequent invasive carcinoma (equal predisposition in both breasts) compared to DCIS
  • Localization: multifocal [29]
  • Pathology
    • Decreased E-cadherin expression
    • Lobules filled with monomorphic cells
    • Intact basal membrane
    • Diffuse growth pattern
  • Management
    • After core needle biopsy
      • Clinical and imaging follow-up
      • Usually no treatment necessary
    • After surgical excision
      • Classic LCIS: no further surgery is necessary
      • Nonclassic LCIS (e.g., pleomorphic LCIS): evaluation of surgical margins and re-excision is recommended


Types and pathophysiology [31][32]

Physiological gynecomastia

Pathological gynecomastia

Some Hormones Cause Fulminant Kleavage: Spironolactone, Hormones, Cimetidine, Finasteride, Ketoconazole cause gynecomastia.

Idiopathic gynecomastia

  • Up to 25% of patients

Clinical features

Diagnostics [40]

Differential diagnoses

Treatment [41]


Clinical features

  • Firm, nontender mass, typically located in the sub-areolar region
  • Pain suggests secondary infection.

Diagnostics [42]

Primarily a clinical diagnosis

  • Fine needle aspiration: milky substance (diagnostic and therapeutic)
  • Ultrasound
    • Complex mass
    • Findings depend on the fat and water content of the cyst
  • Mammography (rarely indicated): Galactoceles may appear as an indeterminate mass or a mass with the classic fat-fluid level.

Differential diagnosis

Differential diagnosis of galactocele
Content Ultrasound Mammography
  • Fat content very high
Cystic mass with fat-fluid level
  • Fresh milk, and variable proportions of fat and water
  • Fat-fluid level on mediolateral view
  • A mix of hypoechogenic and hyperechogenic areas
  • Circumscribed mass with characteristic heterogeneous density due to the presence of fat radiolucencies


  • Usually not necessary (most cases resolve spontaneously)
  • Repeated needle aspiration or surgical excision for symptomatic cysts



Clinical features



Prognosis [44]

  • Cyclical mastalgia
    • Usually resolves spontaneously within 3 months of onset
    • Typically relapses and remits
  • Noncyclical mastalgia
    • Resolves spontaneously in approx. 50% of patients
    • Usually responds poorly to treatment
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