• Clinical science

Benign breast conditions


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, 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.


Epidemiology Clinical features Diagnosis Treatment
Fibrocystic changes
  • Most common benign lesion of the breast
  • Most common in nursing mothers
  • Clinical
  • In nursing mothers: frequent emptying of the breast
  • Analgesics and cold compresses
  • Antibiotics (dicloxacillin)
Fat necrosis
  • < 3% of all breast lesions
  • Peak incidence: 50 years
  • Often associated with soft tissue trauma
  • 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
  • Ultrasound and/or mammogram
  • Core needle biopsy
  • Surgical excision
Intraductal papilloma
  • Peak incidence
    • Solitary lesions: ∼ 48 years
    • Multiple lesions: ∼ 41 years
  • Core needle biopsy
  • Surgical excision


Congenital anomalies of the breast

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

Fibrocystic changes

  • Definition: benign changes characterized by the formation of fibrotic and/or cystic tissue
  • Epidemiology
    • Most common benign lesion of the breast
    • Up to 50% of women are affected during their lifetime.
    • Primarily in premenopausal women 20–50 years of age
  • Etiology: unknown
  • Clinical features
  • Diagnosis
    • Physical exam
    • First-line: ultrasound and mammogram
      • Ultrasound: Findings range from normal appearance to focal regions of thick parenchyma; cysts 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
    • General approach
      • If symptoms are mild, treatment is not required.
      • In case of severe symptoms: oral contraceptives, tamoxifen , or progesterone
      • Fine-needle aspiration or surgery
        • If a cyst causes severe pain, discomfort, or disfiguration
        • In case of proliferative lesions with atypical cells
      • Reevaluate the cyst after 4–6 weeks.
      • Detailed approach
        • Nonproliferative lesions/proliferative lesions without atypia: pharmacotherapy
          • Progestogen replacement therapy
          • Administration of antiestrogen
          • Last resort: combination of prolactin secretion inhibitor (e.g., bromocriptine) and gonadotropin inhibitor
        • Proliferative lesions with atypia: surgery
          • Frequent monitoring with annual mammogram and ultrasound
          • Detection of abnormalities
            • Excision of the nodular changes
            • Subcutaneous mastectomy with nipple preservation
  • Prognosis: 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



  • Definition: inflammation of the breast parenchyma
  • Epidemiology
    • Incidence: up to 10% of nursing mothers (particularly 2–4 weeks postpartum)
    • Incidence of periductal mastitis : 5–9% of non-lactating women
  • Etiology
  • Pathophysiology
    • Most frequently in women with nipple fissures , prolonged breast engorgement (e.g., because of overproduction of milk or insufficient milk drainage (e.g., infrequent feeding, quick weaning, illness in either the baby or mother)
    • Bacteria located in the nostril and throat of the infant or on the skin of the mother enter milk ducts during breastfeeding → pathogen flourishes in stagnant milk → tissue inflammation
    • The pathophysiology of periductal mastitis is not well known, but smoking causes inflammatory damage to subareolar ducts, with tissue necrosis and secondary infection.
  • Clinical features
  • Diagnosis
    • Clinical diagnosis
    • Breast milk cultures or imaging may be required if there is no response to initial treatment.
  • Treatment

A fluctuant mass may indicate a breast abscess.

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


Fat necrosis of the breast

  • Definition: nonsuppurative inflammatory lesion affecting breast adipose tissue
  • Etiology: trauma
  • Epidemiology
    • Incidence: < 3% of all breast lesions
    • Peak incidence: 50 years
  • Clinical features: irregularly defined and dense breast mass (generally periareolar) causing skin retraction, erythema, or ecchymosis
  • Diagnosis
    • Mammogram and/or ultrasound: fluid-filled cyst
      • Also on mammogram: coarse rim calcification
    • If any suspicious or inconclusive imaging findings → perform biopsy
  • Treatment: unnecessary


Benign breast neoplasms


  • Definition: : benign breast tumor with fibrous and glandular tissue
  • Etiology: unknown, but a hormonal relationship has been established (increased estrogen, e.g., during pregnancy or before menstruation, may stimulate growth)
  • Epidemiology
    • The most common breast tumor in women < 35 years of age
    • Peak incidence: 15–35 years
  • Clinical features: mostly solitary : , well-defined, non-tender, rubbery, and mobile mass
  • Diagnosis
    • Ultrasound: well-defined mass
    • Mammogram: well-defined mass that may have popcorn-like calcifications
    • If imaging is inconclusive: fine-needle aspiration showing fibrous and glandular tissue
  • Treatment: regular check-ups

Phyllodes tumor

  • Definition: rare fibroepithelial tumor with histology similar to that of fibroadenoma
  • Etiology: unknown
  • Epidemiology
    • 1% of all breast tumors
    • Most commonly benign
    • Peak incidence: 40–50 years
  • Clinical features
    • Painless, smooth, multinodular lump in the breast
    • Variable growth rate: may grow slowly over many years, rapidly, or have a biphasic growth pattern
    • Average size 4–7 cm
  • Diagnosis
  • Treatment
    • Surgical excision
    • In case of recurrence: total mastectomy
  • Prognosis
    • After excision of benign tumors: excellent prognosis
    • Lesions that show signs of malignancy on histology may recur and metastasize.

Intraductal papilloma

  • Definition: solitary or multiple benign lesions that arise from the epithelium of breast ducts
  • Etiology: unknown
  • Epidemiology
    • Peak incidence: 40–50 years
      • Solitary lesions: ∼ 48 years
      • Multiple lesions: ∼ 41 years
  • Clinical features
    • 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 than solitary papilloma
  • Diagnosis
    • If lesion is palpable: Core needle biopsy is confirmatory and rules out malignancy.
      • Shows papillary cells with fibrovascular core
    • Otherwise: ductogram : nonspecific findings such as ectasia and filling defects
  • Treatment: surgical excision of the affected duct
  • Prognosis: generally excellent



Types and pathophysiology
Physiological gynecomastia
Pathological gynecomastia
Idiopathic gynecomastia
  • Up to 25% of patients



  • Definition: milk retention cyst located in the mammary gland
  • Epidemiology
    • Most common benign breast lesion in lactating women
    • Frequently occurs during or after lactation
  • Pathophysiology: obstruction of lactiferous duct → distention of the duct due to collection of milk and epithelial cells → cyst formation
  • Clinical features
    • Soft, nontender mass; typically located in the sub-areolar region
    • Pain suggests secondary infection.
  • Diagnosis
    • 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
Content Ultrasound Mammography
  • Fat content very high
  • Radiolucent
Cystic mass with fat-fluid level
  • Fresh milk, and variable proportions of fat and water
  • Fat echogenicity is higher than fluid
  • Fat-fluid level is visible on medio-lateral view
  • Old milk, and variable proportions of fat and water
  • Mixture of hypoechogenic and hyperechogenic areas
  • Circumscribed mass with characteristic heterogeneous density due to the presence of fat radiolucencies
  • Treatment
    • Usually not necessary (most cases resolve spontaneously)
    • Repeated needle aspiration or surgical excision for symptomatic cysts
  • Prognosis: good; no increased risk of subsequent breast cancer