Benign Breast Conditions

Nonproliferative Epithelial Breast Lesions

Definition

Nonproliferative breast lesions are conditions generally not associated with an increased risk of breast cancer.

Simple breast cyst

• Round or oval fluid-filled masses from the terminal duct lobular unit
• Epidemiology:
  • Prevalence: estimated to be 50%–90%
  • Up to ⅓ of women aged 30–50 have breast cysts
• Clinical presentation:
  • Felt as a palpable mass
  • Pain noted with acute enlargement of cyst
• Diagnosis:
  • Ultrasonography (US): 
    • Differentiates masses (solid, fluid-filled, or with mixed elements)
    • Simple cyst: well-circumscribed, anechoic, with no solid components
  • Mammogram: oval or round shape with circumscribed margins
• Management:
  • No further intervention most of the time
  • Fine needle aspiration
    • For signs of infection or inflammation 
    • Pain from increased size

Mild hyperplasia of the usual type

• Pathology: 
  • Cells look very close to normal. 
  • An increase in the number of epithelial cells within a duct
  • Cell depth is more than 2 but not more than 4 cells.
• Clinical presentation: found on biopsy or surgical excision
• Management: no treatment needed

Papillary apocrine change

• Pathology: 
  • Proliferation of ductal epithelial cells with apocrine features
  • May be simple, complex, or highly complex lesions 
• Clinical presentation: found on histological examination (biopsy or surgical excision)

Proliferative Epithelial Lesions without Atypia

Definition

In proliferative breast lesions without atypia, the development of breast cancer is 1.5–2 times the risk of the general population.

Intraductal papilloma

• Benign mass with a papillary configuration of breast stroma and epithelium within a breast duct
• Epidemiology:
  • Peak incidence: 30–50 years of age
  • < 10% of benign breast lesions
  • High-risk precursor lesion with the following predisposing factors:
    • Contraceptive use
    • Hormone replacement therapy
    • Family history of breast cancer
• Clinical presentation: depends on the size and location
  • Central type:
    • Frequently a solitary mass, close to or behind the nipple within principal lactiferous ducts
    • Usually large enough to be palpated
    • Unilateral serous or bloody nipple discharge: a common presentation
    • Mostly benign
  • Peripheral type: (10% of cases)
    • Often appears as multiple papillomas and affects younger premenopausal women 
    • Found on the outer areas of the breast (growth in terminal ducts)
    • Usually non-palpable and less likely to have discharge
    • Appears as mammographic calcifications
    • Increased risk for breast cancer
• Diagnosis:
  • Mammography: 
    • Can be occult
    • When seen, oval/round mass; margins can be ill-defined
    • May have calcifications
  • Core needle biopsy (CNB) (guided by ductogram or US):
    • Preferred over fine needle biopsy (risk of inadequate tissue sample)
    • Shows papillary cells with a central branching fibrovascular core
• Management: 
  • Surgical excision/lumpectomy with complete removal: due to risk of atypical ductal hyperplasia or ductal carcinoma in situ (DCIS)
  • Annual breast exam and mammogram

Simple fibroadenoma

• A benign solid breast mass composed of fibrous and glandular tissue
• Epidemiology:
  • Most common benign tumor of the breast
  • Peak incidence: 15–35 years of age
  • For majority, no potential for cancer
  • Risk factors of subsequent cancer:
    • Proliferative histology
    • Complex mass 
    • Family history of breast cancer
• Clinical presentation:
  • Small, well-defined, spherical, mobile mass 
  • Rubbery or firm consistency, non-tender
  • Size: usually ≤ 3 cm in diameter, solitary
  • Location: often in the upper outer quadrant
  • Mass size and tenderness influenced by estrogen levels:
    • Increased size: pregnancy, lactation, pre-menstruation, and oral contraceptives
    • Regresses after menopause
• Diagnosis:
  • US: well-defined solid mass, regular boundaries, and a weak echo signal
  • Mammogram: 
    • Well-circumscribed oval mass, may have lobulations
    • Popcorn-like calcifications in involuting fibroadenomas
  • Biopsy:
    • Indications: 
      • > 5 cm or increasing size
      • Irregular borders 
      • Considerable pain
    • Cytology: uniformly distributed epithelial cells (honeycomb or antler-like pattern)
    • Microscopy: stroma and epithelial cells either in pericanalicular or intracanalicular pattern
  • MRI: may have dark internal septations
    • T1: iso- or hypointense to normal parenchyma
    • T2: varies with amount of myxoid or fibrous elements
• Management:
  • Fibroadenoma with benign features: observation, breast exam, and annual mammogram
  • Cryoablation: an option for small but symptomatic fibroadenomas 
    • CNB done first to confirm diagnosis
    • Criteria:
      • For fibroadenomas < 4 cm in size, < 3 in number
      • No bleeding tendency and no local skin infection 
  • Surgical excision for: 
    • Adolescent-onset fibroadenoma persisting through adulthood (risk of breast cancer increases)
    • Increase in size or with atypical features or symptoms

Radial scars

• Complex sclerosing lesions
• Clinical presentation: 
  • Incidental finding in a biopsy done for other reason
  • If large, seen in mammogram as an architectural distortion
• Pathology: fibroelastic core with radiating ducts and lobules
• Management: surgical excision as lesions may be premalignant (up to 17% have malignancy)

Sclerosing adenosis

• Enlarged and distorted lobules (milk-producing sacs) with stromal fibrosis and interspersed glandular cells
• Clinical presentation: felt as a palpable mass
• Diagnosis: 
  • Mammogram: calcifications, well-circumscribed to spiculated mass
  • CNB
• Management: 
  • Small risk of subsequent malignancy
  • Observation with annual breast exam and mammogram

Usual ductal hyperplasia

• Pathology: increased cells in ductal space or lobule (without atypia)
• Clinical presentation: seen incidentally on biopsy or as calcifications on mammogram
• Management:
  • Small risk of subsequent malignancy
  • Observation with annual breast exam and mammogram

Benign Epithelial Breast Lesions with Atypical Hyperplasia

Atypical ductal hyperplasia (ADH)

• Found in 5%–20% of breast biopsies
• Moderate increase in breast cancer risk
• Clinical presentation: too small for palpation, discovered incidentally on biopsy (for mammographic findings such as calcifications)
• Diagnosis: 
  • CNB
  • Pathology: proliferation of monomorphic epithelial cells in the breast duct
  • Shares features of low-grade DCIS without meeting full criteria
• Management: 
  • Surgical excision: standard of care (ADH is premalignant) 
  • Breast exam every 6–12 months and annual mammogram
  • Avoid hormone replacement therapy, oral contraceptives
  • Lifestyle and dietary changes

Atypical lobular hyperplasia (ALH)

• Increased risk of developing breast cancer in either ipsilateral or contralateral breast
• Clinical presentation: discovered incidentally on biopsy (for mammographic findings such as calcifications)
• Diagnosis:
  • Pathology: Within the acini of terminal duct lobular unit, there is over-proliferation of dyshesive epithelial cells.
  • Shares features of lobular carcinoma in situ or invasive lobular carcinoma without meeting full criteria
• Management:
  • Surgical excision is generally appropriate but not routine.
  • Excision for high-risk patients (family/personal history of breast cancer, BRCA1 or BRCA2 mutation)
  • In carefully selected lower-risk patients: 
    • Estrogen receptor modulators
    • Increased mammogram and follow-up frequency 
  • Risk-reduction measures: 
    • No hormone replacement therapy, oral contraceptives
    • Lifestyle and dietary changes

Flat Epithelial Atypia

• A distinct lesion from ADH and ALH 
• Flat growth pattern (does not meet architectural criteria of ADH)
• High-risk or atypical breast lesion but risk remains undefined
• Clinical presentation: discovered on biopsies done for mammographic calcifications
• Diagnosis: pathology characterized by columnar changes with atypia
• Management:
  • Surgical consultation with risk assessment
  • Observation is an option along with frequent exam and mammogram.

Breast Abscess

• Epidemiology: usually associated with mastitis 
  • Known risk factors (in lactating women): 
    • Age > 30 years
    • Primiparous
    • Late delivery
    • Smoking
  • Known risk factors (in non-lactating women):
    • African American
    • Obesity 
    • Diabetes 
    • Smoking
• Clinical presentation:
  • Unilateral and fluctuant mass
  • Painful, erythematous, and edematous breast 
  • Possible purulent discharge from the nipple
  • Fever
• Diagnosis:
  • Clinical: history and findings of a fluctuant, tender, palpable mass 
  • Nipple discharge: Culture may help guide choice of antibiotic. 
  • Ultrasound: ill-defined hypoechoic collection with internal septations
  • Needle aspiration reveals purulent contents. 
• Management:
  • Incision and drainage especially: 
    • If with skin ischemia or pressure necrosis
    • If needle aspiration and/or antibiotics fail
  • Needle aspiration:
    •  Can be an initial treatment if overlying skin is not ischemic or abscess(es) < 3 cm
    • Repeated every 2–3 days until there is no collection
  • Antibiotics that target most common causative agent, Staphylococcus aureus: cephalexin, dicloxacillin, or amoxicillin-clavulanate

Miscellaneous Breast Lesions

Diabetic mastopathy

• Lymphocytic mastopathy or lymphocytic mastitis
• May be due to secondary autoimmune reaction from effects of hyperglycemia on connective tissue
• Seen in up to 13% of patients with diabetes mellitus type 1
• Clinical presentation: painless mass, seen in long-standing diabetes mellitus type 1
• Diagnosis: 
  • Mammogram: solid mass with asymmetric density
  • Ultrasound: irregular hypoechoic mass
  • CNB
• Management: 
  • Excision not needed as there is no increased risk for breast cancer
  • Known to recur after surgical removal
  • Annual mammogram

Sarcoidosis

• Seen in patients with systemic sarcoidosis but mammary involvement can be the sole manifestation
• Clinical presentation: firm breast masses
• Diagnosis:
  • Mammogram: irregular, ill-defined masses
  • CNB: noncaseating granulomas
• Management: 
  • Glucocorticoids
  • Surgical excision an option

Galactocele

• A retention cyst within the mammary gland containing milk 
• An obstruction of a lactiferous duct → accumulation of epithelial cells and milk → distention of the duct → cyst formation
• Epidemiology: most common benign breast condition in lactating women
• Clinical presentation:
  • Palpable, firm mass in the subareolar region
  • Presents with no fever or pain (pain suggests secondary bacterial infection)
  • Unilateral
• Diagnosis:
  • Mainly clinical
  • Fine needle aspiration reveals milky contents
  • Mammogram:
    • Complex cystic masses
    • With fat/fluid levels (from the layering of portions of retained milk)
  • Ultrasound:
    • Depends on the fat and water cystic content
    • Typically, a homogeneous hypoechoic lesion with acoustic attenuation, well-defined margins, and thin walls
• Management: 
  • Most cases resolve spontaneously.
  • Increased breastfeeding, warm compresses, and massage 
  • Repeated needle aspiration or surgical excision: for symptomatic cysts

Phyllodes tumor

• Cystosarcoma phyllodes
• Fibroepithelial tumor similar to fibroadenomas, characterized by rapid growth
• Epidemiology:
  • Most common in women between 40 and 50 years of age
  • Account for < 1% of all breast neoplasms
  • Although usually benign, some may become malignant (25% of cases)
• Clinical presentation:
  • Painless, multinodular, firm, rapidly growing mass 
  • Usually 4–7 cm in diameter
  • About 20% nonpalpable, identified on mammography
• Diagnosis:
  • Mammography: lobulated mass, resembles fibroadenoma
  • Ultrasonography: well-defined, hypoechoic mass (like fibroadenomas, without microcalcifications)
  • MRI: well-circumscribed with irregular walls, high signal intensity on T1, and low signal intensity on T2 
  • CNB: 
    • Papillary projection (phyllodes/“leaf-like”) of proliferating epithelium-lined stroma 
    • Varying degrees of atypia and hyperplasia (depends on benign or malignant nature)
• Management: 
  • Surgical resection with wide margins (due to high recurrence rate)
  • Breast exam and mammogram every 6 months for 2 years, then annually

Giant juvenile fibroadenoma

• Approximately 0.5%–2% of all fibroadenomas
• Usually occurs in African American adolescents
• Clinical presentation:
  • Rapid increase in size; unilateral tumors > 5 cm in diameter
  • May cause skin ulceration and venous engorgement
• Management: surgical excision (as they are not easily distinguished from phyllodes tumors on examination or imaging studies)

Complex fibroadenoma

• Fibroadenoma containing pathologic features: 
  • Sclerosing adenosis
  • Duct epithelial hyperplasia
  • Cysts > 3 mm  
  • Apocrine metaplasia
• Slight increase in cancer risk
• Clinical presentation: presents as a palpable lump or mass on breast imaging
• Diagnosis: biopsy distinguishes it from simple fibroadenoma
• Management: observation, risk assessment with annual exam and mammogram

Differential Diagnosis

• Fibrocystic changes of the breast: refers to the changes that happen to breast tissue as a woman ages. The normal histologic appearance of predominant ducts, lobules, intralobular stroma, and interlobular stroma is replaced by fibrous tissue and cystic formation.
• Fat necrosis of the breast: usually due to breast injury. As the damaged breast tissue is repaired, it is replaced by scar tissue. Some fat cells may have a different response, however, and form what are known as oily cysts (seen in mammogram and ultrasound).
• Gynecomastia: unilateral or bilateral breast enlargement in males due to increased glandular proliferation. A very common and mostly physiologic condition that is seen in neonates, pubertal boys, and elderly patients. Some cases are pathologic and are secondary to drugs, hyperthyroidism, neoplasms, and chronic liver and kidney disease.
• Mastitis: inflammation of the mammary gland tissue, which can be lactational or non-lactational. Mastitis is most common in women in the childbearing years.