The unique anatomic structure of the breast contributes to the wide variety of pathologic conditions that may occur. Each breast contains approximately 20 glandular units (lobes) composed of glands and adipose tissue (Fig. 127.1). Each lobe drains into a lactiferous duct, which fuses with other ducts to form lactiferous sinuses just below the skin. The lactiferous sinuses store milk during lactation. Disruption (obstruction, infection, inflammation) of the glandular system may occur at any time during a female’s lifetime but predominates between menarche and menopause. The breast’s diffuse vascular network predisposes it to hematogenous spread of malignancy, as well as infection.

Fig. 127.1 The breast contains approximately 20 glandular units (lobes), each composed of a tubuloalveolar gland and adipose tissue.

(From Iglehart JD, Kaelin CM. Diseases of the breast. In: Townsend CM, Beauchamp RD, Evers BM, et al, editors. Sabiston’s textbook of surgery. 17th ed. Philadelphia: Saunders; 2004.)

Virtually all breast conditions that occur in women are seen in men as well, including benign conditions such as fat necrosis, allergic and irritant dermatitis, mastitis and abscess, and mammary tuberculosis. Malignant entities such as adenocarcinoma of the breast, Paget disease of the nipple, and lymphoma occur less frequently in men than in women. Breast cancer in men accounts for less than 1% of the total number of breast malignancies diagnosed in the United States. However, in other areas in the world (e.g., central Africa), male breast cancer is significantly more common. Men are at higher risk for the development of malignant melanoma and basal cell carcinoma of the breast. One condition, gynecomastia, occurs exclusively in men.

Presenting Signs and Symptoms

Differential Diagnosis and Medical Decision Making

See Box 127.1 for an overview of causes of breast-related complaints.

Mastalgia

Breast pain, especially as an isolated symptom, can be thought of as originating from one of three broad categories: cyclic mastalgia, noncyclic mastalgia, or extramammary.

Cyclic mastalgia occurs in premenopausal women, is associated with worsening symptoms in the late luteal phase of the menstrual cycle, and accounts for two thirds of patients with mastalgia. The typical pain of cyclic mastalgia is “achy” or “heavy” and bilateral. Resolution with the onset of menses is very reassuring.

Findings on physical examination may be normal, or tender nodularities may be detected. Fibrocystic breast conditions (the term fibrocystic breast disease has been replaced by the term fibrocystic breast condition to emphasize that it represents a spectrum of histologic entities) are not associated with axillary lymphadenopathy, skin thickening, edema or discoloration, or nipple abnormalities such as retraction or discharge. The presence of any of these findings raises the probability that the patient has another condition instead of or in addition to cyclic mastalgia.

Noncyclic mastalgia may be caused by a variety of conditions ³ (Box 127.2). It may be constant or intermittent, but it is not associated with the menstrual cycle. Noncyclic mastalgia tends to be unilateral and localized to a discrete area. Women with noncyclic breast pain are generally older than 40 years, and the cause is likely to be related to an anatomic lesion in the breast. It is rare for breast cancer to have pain as the sole initial symptom.⁴

Extramammary breast pain can arise from the chest wall or from other sources. Although most of the conditions that cause isolated breast pain are not immediately life-threatening, some emergency conditions, including acute coronary syndrome and pulmonary embolism, can be accompanied by pain that appears to be originating from the breast.

Mondor disease (Fig. 127.2) is a superficial phlebitis of the lateral thoracic, thoracoepigastric, or superior epigastric vein. It typically occurs in middle-aged women. The condition can be unilateral or bilateral. It is often idiopathic but may be associated with other conditions.⁵ The classic Mondor cord is 2 to 3 mm in diameter and typically red and tender, tracks from the lateral margin of the breast across the costal margin, and extends from 2 to 30 cm. Any tenderness should resolve within weeks, but the cord may remain palpable for up to 6 months. There is no risk for systemic embolization.

Fig. 127.2 Mondor disease.

(Photo courtesy Edward Pechter, MD.)

Dermatologic Changes and Discharge

A wide variety of skin conditions can affect the breast, nipple, or both; the most threatening and most common are listed in Box 127.3 and are discussed in the following sections.

Mammary Paget Disease

Paget disease of the nipple (Fig. 127.3, A and B), first described by James Paget in 1874, is a neoplastic condition that accounts for 2% to 4% of breast malignancies. The lesion involves the nipple-areola complex and may spread to the surrounding skin. Patients with early disease may have only a burning and itching sensation around the nipple area. A central palpable breast mass is present in 60% of cases.⁷ Patients with mammary Paget disease usually undergo mastectomy with either lymph node dissection or sentinal node biopsy.

Fig. 127.3 A and B, Paget disease of the nipple.

(Courtesy Sehwan Han, MD.)

Skin Necrosis

Warfarin-induced skin necrosis is a rare complication of oral anticoagulant therapy that affects only 0.01% to 0.1% of patients who take the medication.⁸ The typical patient is a middle-aged, obese woman who recently initiated Coumadin therapy, although cases have been reported occurring well into a year of therapy.

The lesions can be single or multiple and are accompanied by intense pain.

Masses

Although breast pain is the most common symptom causing women to seek medical care related to their breasts, a palpable breast mass is associated with significant anxiety and frequently prompts a visit to a physician. For patients with a chief complaint of a breast mass, evaluation and treatment will probably be based on findings on physical examination, the patient’s age, and other risk factors.

Breast cancer is exceedingly rare in women younger than 20 years and accounts for only a small fraction of a percent of breast disease in women younger than 30 years. Most women younger than 35 years with a solitary painless breast mass will have a fibroadenoma (see Table 127.1 for a comparison of benign breast tumors). Common benign breast masses include fibroadenomas, cysts, phyllodes tumors (malignant 5% of the time), and intraductal papillomas. Other benign tumors found in breast tissue, but not limited to the breasts, include lipomas, hamartomas, hemangiomas, neurofibromas, granular cell tumors, and fat necrosis. None of these conditions appear to increase the risk for subsequent development of breast cancer.

Table 127.1 Benign Breast Tumors

Breast Cancer

Emergency physicians (EPs) are in a unique position to provide education about breast cancer and screening (Box 127.4) to many women who do not have other contact with the health care system,⁹^–¹¹ in particular, minority and lower socioeconomic groups, who have both higher mortality rates and decreased access to preventive services. A female born in the United States today has a 13% probability of breast cancer developing during her lifetime. Most women in whom breast cancer develops have only two risk factors (being female and age older than 50 years).

Box 127.4

American Cancer Society Recommendations for Breast Cancer Screening, 2010

Women 40 years and older should have a screening mammogram every year and should continue to do so for as long as they are in good health.

Breast self-examination (BSE) is an option for women starting in their 20s. Women should be told about the benefits and limitations of BSE. Women should report any changes in their breasts to their health professional right away.

Women in their 20s and 30s should have a clinical breast examination (CBE) as part of a periodic (regular) health examination by a health professional at least every 3 years. After 40 years of age, women should undergo CBE by a health professional every year.

Women at high risk (greater than 20% lifetime risk) should undergo magnetic resonance imaging (MRI) and mammography every year. Women at moderately increased risk (15% to 20% lifetime risk) should talk with their doctors about the benefits and limitations of adding MRI screening to their yearly mammogram. Yearly MRI screening is not recommended for women whose lifetime risk for breast cancer is less than 15%.

From American Cancer Society guidelines for breast cancer screening. Available at www.cancer.org. Revised 2/9/11.

Complications of Breast Cancer

Patients undergoing treatment of breast cancer frequently visit the ED because of complications related to their disease or treatment. Breast cancer metastasis commonly includes local, regional, and distant sites: lung, pleura, pericardium, bone, and brain. Because breast cancer is the most common extrathoracic primary neoplasm that causes metastases to the heart and pericardium, the EP should facilitate emergency echocardiography when managing a patient with breast cancer and symptoms consistent with pericardial effusion.

The development of back pain in a woman with a history of breast cancer should prompt initiation of diagnostic studies and treatment of cord compression. The most sensitive imaging study is magnetic resonance imaging, and it should be performed for back pain even when no associated neurologic finding is present (waiting for symptoms to appear may be too late).

Most patients who are treated for breast cancer undergo surgery that includes some degree of lymph node dissection. Lymphedema affects 10% to 30% of women who undergo axillary lymph node dissection; radiation and infection increase the risk. Lymphedema may range from mild to severe and can develop even years after treatment. Those at risk for the development of lymphedema are encouraged to have blood drawn and intravenous lines placed in the unaffected arm. It is usually permanent, although a few institutions have reported success with autologous lymph node transplantation.¹²

Women who choose lumpectomy or partial mastectomy usually undergo 6 weeks of external beam radiation therapy. Radiotherapy may also be given in the form of radioactive seeds placed at the tumor site. In another method, a saline-filled balloon is placed in the lumpectomy site and radioactive material is instilled and drained twice daily for 5 days. Regardless of the radiation method, the most common complications are radiation-induced dermatitis ¹³ (90% of patients), which can progress to dry desquamation (50% of patients) in the first few weeks, and moist desquamation (<10% of patients), which appears within 3 to 6 weeks. A corticosteroid cream such as mometasone furoate can be used as prophylaxis or treatment of dry desquamation, preferably in consultation with a medical or radiation oncologist. Wet desquamation, a partial-thickness injury, is best treated with hydrocolloid dressings and should be managed in consultation with a plastic surgeon or radiation oncologist.

Late effects of radiation may develop months or years after therapy. Pneumonitis is typically manifested as cough, fever, and shortness of breath 1 to 10 months after completion of radiation therapy. Radiographic changes, which can start as diffuse haziness and progress to patchy consolidations, are generally confined to the field of radiation. Dermal necrosis is a complication that may develop years after treatment. Radiation-induced brachial plexopathy,¹⁴ which may develop up to 30 years after breast cancer therapy, is a permanent debilitating condition that can progress to complete sensory and motor impairment of the ipsilateral upper extremity and chronic neuropathic pain.

Adverse reactions to chemotherapy are beyond the scope of this chapter. However, the EP should be aware of all drugs being used by the patient. In addition, the EP should always query patients about their use of complementary and alternative medicine.

Trauma

Trauma to the breast can be divided into the traditional divisions of blunt and penetrating. All but the most minimal trauma to the breast will require additional consideration of disruption of the underlying structures. The breast tissue itself may diminish the utility of physical examination in accurately identifying pathology.

Blunt trauma to the breast rarely appears in isolation. Multiple thoracic injuries are typical. Mandatory three-point lap-shoulder restraint laws have been effective in decreasing overall mortality from motor vehicle crashes; however, there has been a concurrent increase in the incidence of soft tissue injury to the chest wall. The chest restraint belt produces both shearing and compressive force. Simple hematomas are the most common problem after trauma. Although these hematomas typically resolve spontaneously, they may recur and become infected, even months after an injury.

Crush injuries from seat belts that involve the breast have, in rare cases, caused subcutaneous transection of the breast. A permanent furrow deformity may result. Because the breast is mobile over the pectoral fascia, sudden forceful movement of the breast can also cause complete avulsion of the breast from the chest wall and potentially rupture the perforating arteries to the breast. A transected artery may bleed massively immediately or may retract into the pectoral musculature and result in life-threatening hemorrhage after the vascular spasm resolves.

Fat Necrosis

The most common long-term complication after trauma to the breast is fat necrosis.¹⁵ Fat necrosis is an inflammatory condition that is typically a sequela of trauma, but it may also develop following surgery, infection, or radiation therapy. Women with pendulous breasts seem to be at higher risk for fat necrosis. The pathophysiology is multifactorial but primarily involves the breakdown of fat cells by blood and tissue lipases. Clinically, mammographically, and sonographically, the condition may mimic carcinoma of the breast. Usually, a firm, poorly mobile, nontender mass is present in the superficial subcutaneous tissues. The overlying skin may be erythematous, ecchymotic, or indurated. Axillary lymphadenopathy and nipple retraction may be present. Fat necrosis typically resolves spontaneously but requires biopsy to reliably differentiate it from malignancy.

Perioperative Complaints

More than 2 million women in the United States have undergone breast augmentation. Although 80% of augmentations are performed purely for cosmetic reasons, the 20% representing reconstruction following mastectomy account for a disproportionate percentage of local complications. Roughly 30% will require additional surgeries within 5 years.¹⁶

Postoperative pain can be prolonged; 30% to 40% of patients report significant pain 1 year after reduction or augmentation mammoplasty, and the number is higher after mastectomy with reconstruction. Phantom breast pain after mastectomy occurs in up to 12% of patients 1 year after surgery.¹⁷

Seroma or Hematoma

The most common perioperative complication after any type of breast surgery is a seroma, or collection of serous fluid. On physical examination, the accumulation is manifested as a soft, movable mass with no evidence of infection and a “water bed” consistency when depressed and released. Seromas typically appear 7 to 10 days after surgery or 1 to 2 days after removal of a drain; in most cases they will resolve independently as the fluid is absorbed into surrounding tissues. A persistent, untreated seroma can lead to infection or skin flap necrosis. Hematomas may also occur after surgery, and management depends on multiple factors, including size and when they develop in relation to surgery.

Galactorrhea

In the first days of recovery from surgery, 1% of women will experience galactorrhea (inappropriate lactation). This figure is slightly higher in women who have previously breastfed.

Capsular Contracture

In capsular contracture, tightly woven collagen fibers form about an implant; they represent the body’s attempt to isolate the implant from endogenous tissue. In 15% of women, this capsule becomes hard and resistant, contracts around the implant, and causes pain, deformation, and rupture. The risk is greater in women who experienced perioperative seroma, hematoma, or infection and in those who opt for silicone implants or subglandular placement.

Rupture

The median life span of an implant is approximately 16 and 10 years for silicone gel and saline prosthetics, respectively. Although most ruptures do not result from ascertainable trauma, they have been reported following mammography, motor vehicle collisions, gunshots, falls, and surgical procedures in the chest, including central venous catheter insertion and thoracostomy. Clinical examination alone is unsatisfactory to identify most ruptures and should be supplemented with magnetic resonance imaging (90% accurate) or computed tomography (80% accurate).

Infection

Many surgeons advocate perioperative antibiotic prophylaxis. This precaution has decreased the rate of postoperative infections, which otherwise ranges from 2% to 4% within the first month. The highest risk for infection occurs in patients who choose reconstruction at the time of mastectomy. The most common pathogen is Staphylococcus aureus (75%), followed by Staphylococcus epidermidis (10%). Toxic shock syndrome has been reported in some patients after augmentation or explantation; patients exhibit sudden pyrexia (>102° F), swelling of the infected breast, vomiting, diarrhea, dizziness, and often a sunburnlike rash.

Lactation and Puerperal Changes

Puerperal Mastitis

Puerperal mastitis, or mastitis that develops while breastfeeding, is a common cause of premature cessation of lactation and results in voluntary discontinuation of breastfeeding in up to 25% of patients.¹⁸ It develops in about one third of nursing mothers. Eighty percent of cases occur in the first 3 months of lactation. Mastitis can rarely progress to abscess formation; this is significantly more common in the first 6 weeks after birth. Risk factors for puerperal mastitis include older age, primiparity, nipple damage, employment outside the home, ineffective nursing technique, and milk stasis.

Symptoms of puerperal mastitis include a painful, erythematous area or mass on the breast and systemic symptoms of fever, chills, malaise, and myalgia. The most common causative organism is S. aureus, although other organisms have been identified and infections may be polymicrobial. Fungal infection in the lactating breast is more common than was previously thought. C. albicans is the most frequently identified organism.

Differentiating between mastitis and abscess is important, and it is possible that the two conditions exist on a continuum. However, making the appropriate distinction is significant because the treatment for each is markedly different. Although an abscess is usually associated with significant fluctuance, it may appear as only a focal induration. Ultrasonography of the affected area should be performed to identify a subcutaneous fluid collection.

Risks Associated with Lactation in Special Circumstances

Breastfeeding is superior to manufactured infant formula for its nutritional, cognitive, emotional, and immunologic benefits. Not all medications contraindicated during pregnancy are similarly dangerous to the nursing infant. Inappropriate cross-referencing of drug information in pregnancy to lactation may result in early cessation of lactation. Similarly, not all maternal infections necessitate cessation of lactation ¹⁹ (Table 127.2).

Table 127.2 Breastfeeding Recommendations with Selected Maternal Infections

INFECTION	CLINICAL SIGNIFICANCE AND IMPACT ON BREASTFEEDING
CMV	Rarely causes illness in full-term infants because of placentally acquired antibodies
Hepatitis A	Found in breast milk but is an unusual mode of transmission; give immunoglobulin to the infant and continue breastfeeding
Hepatitis B	Give the infant routine hepatitis B vaccine and immunoglobulin and continue breastfeeding
Hepatitis C	Not proved to be transmitted by breastfeeding; continue breastfeeding.
VZV	Close contact with a person with acute VZV infection requires VZV immunoglobulin; the infant must avoid an infected person until the lesions crust over; expressed breast milk may be given unless lesions are present on the nipple-areola complex
HSV-1 and HSV-2	Breastfeeding can be continued unless lesions are present on the breast
Lyme disease	If organism can be detected in breast milk by PCR but the infant has no signs of clinical illness, continue breastfeeding
Syphilis	Delay breastfeeding and express breast milk until maternal therapy has been given for 24 hr; treat the infant empirically
TB	Transmission via breast milk is seen only with TB mastitis; if no breast lesions are present, stop breastfeeding for 14 days and give isoniazid to the infant; expressed breast milk may be used
Gonorrhea	If the mother is treated with ceftriaxone, continue breastfeeding; if other medications are used, delay breastfeeding for 24 hr

CMV, Cytomegalovirus; HSV, herpes simplex virus; PCR, polymerase chain reaction; TB, tuberculosis; VZV, varicella-zoster virus.

Data from Lawrence RM, Lawrence RA. Breast milk and infection. Clin Perinatol 2004;31:501–28.

On average, 1% to 2% of a maternal dose of a drug is delivered to the infant, although the amount varies depending on the drug. Because the milk compartment is bidirectional, a drug that peaks in milk after 30 minutes may leave the milk compartment before the next feeding. It is therefore recommended that when possible, a nursing mother take medications immediately after a feeding to decrease the amount delivered to the infant in the next feeding. Little evidence-based data are available to determine which drugs are safe to use in lactation. EPs concerned about the safety of a particular medication in a lactating woman can consult the American Academy of Pediatrics Committee on Drugs.²⁰

Administration of radioactive compounds to a lactating mother may require temporary cessation of breastfeeding (Table 127.3). Expression and discarding of milk for the duration of five half-lives are recommended. When ordering a nuclear medicine study for a lactating woman, the EP should speak directly to the nuclear medicine radiologist to determine whether a radionuclide with a shorter half-life could be used.

Table 127.3 Radioactive Drugs That Require Temporary Cessation of Breastfeeding

DRUG	TIME OF CESSATION
Gallium 67	14 days
Iodine 125	12 days
Iodine 131	2-14 days, depending on the study
Radioactive sodium	4 days
Copper 64	50 hr
Technetium 99m	15-36 hr
Iodine 123	36 hr
Indium 111	20 hr