INTRODUCTION	Section 2 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

Background: Patients typically do not present in the ED with a breast mass as their chief complaint; however, knowledge of the pertinent anatomy, pathophysiology, and clinical clues is essential.

Breast masses can be broadly classified as benign or malignant. Common causes of benign breast masses include fibrocystic disease, fibroadenoma, and abscess. Malignant breast disease encompasses many histologic types that include, but are not limited to, in situ lobular or ductal cancer, intraductal papilloma, infiltrating ductal 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.

Pathophysiology: 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. Inflammatory carcinoma is the most aggressive malignant tumor and carries the worst prognosis.

The breast is a modified sweat gland with multiple secretory acini that drain into lactiferous ducts. These ducts are grouped into lobules, which are demarcated by Cooper ligaments. Each of the lobule secretory ducts converge to form one ampulla, which traverses the nipple to open at the apex. When the lactiferous duct lining undergoes epidermalization, keratin production can cause plugging of the duct and result in abscess formation. This helps explain the high recurrence rate (an estimated 39-50%) of breast abscesses in patients treated with standard incision and drainage (I&D). 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 is precipitated by milk stasis.

Frequency:

• In the US: One out of every 8 women is diagnosed with breast cancer during her lifetime. Breast abscess is more common in nonlactating (nonpuerperal) women than in women who are lactating. One study found that, over a 10-year period, 8.5% of 72 women presenting with a breast abscess were in puerperium. Postpartum mastitis occurs in 1-5% of lactating women.

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, and lymphedema.

• Breast abscess: Recurrent or chronic infections, pain, and scarring are causes of morbidity.

• Mastitis: Abscess formation is a complication of postpartum mastitis in fewer than 10% of individuals affected.

Race: Premenopausal breast cancer is more likely to develop in black women than white women. This is not true during the postmenopausal period.

Sex: Breast masses are overwhelmingly a disease of women.

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.

• Fibroadenoma is the most common cause of breast mass in women up to age 35 years.

	CLINICAL	Section 3 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

History:

• Breast mass

• Palpable mass, typically only in one breast

• Family history of breast disease, malignant and benign

• Menstrual and obstetrical histories

• Associated symptoms of pain, nipple discharge, and skin changes (eg, dimpling or inflammation, nipple inversion)

• Length of time present, speed of growth

• No history at all if the mass is found during physical examination

• Breast abscess

• Localized breast area edematous, erythematous, warm, and painful

• History of previous breast abscess

• Associated symptoms of fever, vomiting, and spontaneous drainage from the mass or nipple

• May be lactating

• Mastitis

• Localized breast area erythematous, warm, and painful

• 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 any older woman presenting with unexplained weight loss, anorexia, or bone pain. Talk through the examination, giving extra instruction on how and when patients can perform breast self-examination at home.

• 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

• Skin retraction or tethering

• Axillary lymphadenopathy

• Inflammatory changes of the skin (ie, peau d'orange)

• Breast abscess

• Localized breast area erythematous, hot, edematous, and extremely painful

• Most commonly found in the areolar or periareolar area

• Fluctuance of the mass

• May have associated fever or axillary lymphadenopathy

• Discharge with palpation from nipple or mass

• Nipple inversion

• Mastitis

• Localized breast area erythematous, warm, indurated, and tender

• May have associated fever

Causes:

• 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, menopause after age 55, and late pregnancy.

• The BRCA gene is responsible for 5% of all breast cancers and is inherited in an autosomal dominant fashion. Of those with the gene, 60% develop breast cancer by age 50 years.

• 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.

• Mastitis

• S aureus is most common cause, typically originating from the nursing child. Streptococci, enterococci, Staphylococcus epidermidis, and Escherichia coli are less common.