eMedicine Specialties > Emergency Medicine > Infectious Diseases

Breast Abscess and Masses

Author: Andrew C Miller, MD, Chief Resident and Clinical Assistant Instructor, Departments of Emergency Medicine and Internal Medicine, State University of New York Downstate Medical Center, Kings County Hospital Center
Coauthor(s): Tajinderpal S Saraon, MD,, Chief Resident, Department of Internal Medicine, State University of New York Downstate Medical Center; Mark A Silverberg, MD, FACEP, MMB, Assistant Professor, Assistant Residency Director, Department of Emergency Medicine, State University of New York Downstate College of Medicine; Consulting Staff, Department of Emergency Medicine, Staten Island University Hospital, Kings County Hospital, University Hospital, State University of New York Downstate at Brooklyn
Contributor Information and Disclosures

Updated: Apr 30, 2009

Introduction

Background

Breast masses can be broadly classified as benign or malignant. Common causes of a benign breast mass include fibrocystic disease, fibroadenoma, intraductal papilloma, and abscess. Malignant breast disease encompasses many histologic types that include, but are not limited to, infiltrating ductal or lobular carcinoma, in situ ductal or lobular carcinoma, and inflammatory carcinoma. The main concern of many women presenting with a breast mass is the likelihood of cancer; however, most breast masses are benign.
 
Breast infection most commonly affects women aged 18-50 years; in this age group, it can be divided into lactational and nonlactational infections. The process can affect the skin overlying the breast, where it can be a primary event, or it may occur secondary to a lesion such as a sebaceous cyst as hidradenitis suppurativa.^1,2

Pathophysiology

The mammary glands arise along the milk lines that extend along the anterior surface of the body from the axilla to the groin. During puberty, pituitary and ovarian hormonal influences stimulate female breast enlargement, primarily due to accumulation of adipocytes. Each breast contains approximately 15-25 glandular units know as breast lobules, which are demarcated by Cooper ligaments. Each lobule is composed of a tubuloalveolar gland and adipose tissue. Each lobule drains into the lactiferous duct, which subsequently empties onto the surface of the nipple. Multiple lactiferous ducts converge to form one ampulla, which traverses the nipple to open at the apex. 

Below the nipple surface, lactiferous ducts form large dilations called the lactiferous sinuses, which act as milk reservoirs during lactation.³ When the lactiferous duct lining undergoes epidermalization, keratin production may cause plugging of the duct, resulting in abscess formation.⁴ This may explain the high recurrence rate (an estimated 39-50%) of breast abscesses in patients treated with standard incision and drainage (I&D), as this technique does not address the basic mechanism by which breast abscesses are thought to occur.
 
Postpartum mastitis is a localized cellulitis caused by bacterial invasion through an irritated or fissured nipple. It typically occurs after the second postpartum week and may be precipitated by milk stasis. There is usually a history of a cracked nipple or skin abrasion. Staphylococcus aureus is the most common organism responsible, but Staphylococcus epidermidis and streptococci are occasionally isolated. Drainage of milk from the affected segment should be encouraged and is best achieved by continuing breastfeeding or use of a breast pump.¹  
 
Nonlactating infections may be divided into central (periareolar) and peripheral breast lesions. Periareolar infections consist of active inflammation around nondilated subareolar breast ducts—a condition termed periductal mastitis. Peripheral nonlactating breast abscesses are less common than periareolar abscesses and are often associated with an underlying condition such as diabetes, rheumatoid arthritis, steroid treatment, granulomatous lobular mastitis, and trauma.¹ Primary skin infections of the breast (cellulitis or abscess) most commonly affect the skin of the lower half of the breast and often recur in women who are overweight, have large breasts, or have poor personal hygiene.
 
Breast masses can involve any of the tissues that make up the breast, including overlying skin, ducts, lobules, and connective tissues. Fibrocystic disease, the most common breast mass in women, is found in 60-90% of breasts during routine autopsy. Fibroadenoma, the most common benign tumor, typically affects women younger than 30 years. Infiltrating ductal carcinoma is the most common malignant tumor; however, inflammatory carcinoma is the most aggressive and carries the worst prognosis.

Frequency

United States

• One out of every 8 women is diagnosed with breast cancer during her lifetime.
• Infectious complications occur in as many as 10% of lactating women.⁵ Lactational mastitis is seen in approximately 2-3% of lactating women,^3,6 and consequently breast abscess can develop in 5-11% of women with mastitis.⁶

Mortality/Morbidity

• Breast mass: Morbidity and mortality depends on pathology of the mass. Approximately 1 in 28 (3.6%) women die from breast cancer. Associated morbidity may include scarring, disfigurement, lymphedema, and significant psychologic stress.
• Breast abscess: Recurrent or chronic infections, pain, and scarring are causes of morbidity.
• Mastitis is usually seen in lactating women, but the presence in a nonlactating woman should spur evaluation for an inflammatory carcinoma⁵ or new-onset diabetes. Abscess formation complicates postpartum mastitis in fewer than 10% of cases. 
• Neonatal mastitis usually occurs in term or near-term infants, is twice as common in females, and progresses to development of a breast abscess in approximately 50% of infants.^7,8

Race

White women have a higher incidence of breast cancer than African American women after age 40. In contrast, African American women have a higher incidence rate before age 40 and are more likely to die from breast cancer at every age.⁹

Sex

Breast masses are overwhelmingly a disease of women. Fewer than 1% of breast cancers are found in males. Even neonatal mastitis occurs twice as frequently in females.^7,8

Age

Women older than 40 years account for more than 80% of breast cancer patients. The median age of diagnosis is 64 years.

• Nonpuerperal breast masses encompass the third to eighth decades of life.
• Puerperal breast abscesses and mastitis are commonly found in women of childbearing age, with a mean age of 32 years.¹
• Fibroadenoma is the most common cause of breast mass in women younger than 35 years.

Clinical

History

• Breast mass
  • Palpable mass, typically only in one breast
  • Family history of breast disease, malignant and/or benign
  • Menstrual and obstetrical histories are important.
  • Associated symptoms of pain, nipple discharge, and skin changes (eg, dimpling or inflammation, nipple inversion)
  • Length of time present, speed of growth
• Breast abscess
  • Localized breast edema, erythema, warmth, and pain
  • History of previous breast abscess is common.
  • Associated symptoms of fever, vomiting, and spontaneous drainage from the mass or nipple
  • May be lactating
• Mastitis
  • Localized breast erythema, warmth, and pain
  • May have fever and chills
  • May be lactating and may have recently missed feedings

Physical

Perform a thorough breast examination for any patient presenting with a breast complaint and for any older woman presenting with unexplained weight loss, anorexia, or bone pain.

• Breast mass
  • Firm mass of variable shape and size
  • Fifty percent of masses found in the upper outer quadrant of the breast
  • May have associated pain with palpation, but most are painless 
  • Nipple discharge or inversion
  • Skin retraction or tethering
  • Axillary lymphadenopathy
  • Inflammatory changes of the skin (ie, peau d'orange)
• Breast abscess 
  • Localized breast erythema, warmth, edema, and tenderness
  • Most frequently areolar or periareolar
  • Fluctuance
  • May have associated fever or axillary lymphadenopathy
  • Nipple discharge or inversion
• Mastitis  
  • Localized breast erythema, warmth, induration, and tenderness
  • Fever

Causes

Malignant

• Breast mass
  • Risk factors for breast cancer include female sex, age older than 40 years, family history of breast cancer, nulliparity, menarche before age 12 years, menopause after age 55 years, and late pregnancy.
  • The BRCA1 and BRCA2 genes are responsible for approximately 5% of all breast cancers and are inherited in an autosomal dominant fashion. Women with mutations in either of these genes have a lifetime risk of breast cancer of 60-85%, and a lifetime risk of ovarian cancer of 15-40%.¹⁰

• Fibroadenoma³
  • The most common cause of breast mass in female patients younger than 25 years is fibroadenoma.
  • These arise from the terminal duct lobular unit and appear clinically as singular, firm, rubbery, smooth, mobile, painless masses ranging in size from 1-5 cm.
  • They may grow to a large size, thereby affecting the contours of the overlying skin and overall shape of the breast.
  • Ultrasonography reveals a well-defined hypoechoic homogeneous mass 1–20 cm in diameter.⁵
  • Fibroadenomas appear as multiple masses in 10–15% of patients.⁵
• Phylloides tumor³
  • Phylloides tumor is also known as cystosarcoma phylloides or giant fibroadenoma.
  • Although generally benign, a malignant variant occurs in 10% of cases.
  • Incidence is highest among women in their 40s or 50s.
  • Most common presentation is that of a large (average size, 5 cm), solitary, firm, breast nodule. 
• Papillary adenoma of the nipple³
  • Papillary adenoma is also known as also known as erosive adenomatosis of the nipple, adenoma of the nipple, florid papillomatosis of the nipple, and subareolar duct papillomatosis of the nipple.
  • This is believed to originate in the terminal lactiferous ducts of the nipple and subareolar tissue.
  • Incidence is highest among women in their 40s.
  • It commonly presents with unilateral serous or bloody nipple discharge that increases before menses.
• Breast abscess
  • Staphylococcus aureus and streptococcal species are the most common organisms isolated in puerperal breast abscesses. Nonpuerperal abscesses typically contain mixed flora (S aureus, streptococcal species) and anaerobes.
  • A study by Schafer et al found a significant correlation between cigarette smoking and subareolar breast abscess.¹¹
• Mastitis
  • Mastitis occurs in 2-3% or more of lactating women, with its highest incidence in weeks 2-3 postpartum.^6,12
  • Periductal mastitis comprises 3-4% of all benign lesions of the breast.³
  • S aureus is the most common cause. Streptococci, enterococci, Staphylococcus epidermidis, Peptostreptococcus species, Prevotella species and Escherichia coli are less common causes.
  • True fungal mastitis is rare and should prompt evaluation for coexisting diabetes mellitus.
  • In infants, infections with Shigella, E coli, and Klebsiella species have been reported.⁸

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