Emergency Breast Imaging, What Radiologists Need To Know
How to cite this article: Hussien AR, El-Quadi M, Shaheen R, Elfar M, O’Connell A. Emergency Breast Imaging, What Radiologists Need To Know. Am J Sonogr 2021;4:4.
Awareness by the general radiologist of the various emergent conditions of the breast would enable a better management and appropriate referral, rather than postponing management till a breast radiologist is available for consultation. Early referrals are essential to prevent deterioration of complications including severe infection and even sepsis. There has been a lack of consensus in the past regarding appropriate management and delays in treatment have resulted in worse outcomes which could have been avoided.
Breast-specific emergencies are uncommon but proper management and intervention by the emergency room doctor and radiologists is crucial, and good communication with the breast imaging radiologist can improve the outcome. The most common presentations are mastitis and breast abscess. In some large and busy setting, this type of communication requires some improvement. With the understanding that almost all breast radiologists work on an out patient daytime basis in most practices we wanted to educate the emergency radiologists who encounter these clinical presentation and increase their awareness and fill the gap in communication with the Breast radiologists.
Breast emergencies may require urgent diagnosis and management such as percutaneous biopsy or trauma, emergencies related to infection and milk fistula. It is important for the emergency room radiologist to recognize the clinical and imaging findings of breast emergencies and complications to be able make a timely diagnosis and to understand what can be performed before referral to a breast radiologist on an outpatient basis. It is also important to be able to differentiate the infection from inflammatory breast cancer and the best ways to address the issue to avoid missing an inflammatory cancer.
The purpose of this article is to review the various types of breast emergencies and the characteristic imaging appearances along with the most common interventions and recommended management and possible complications. The emergency situation we are discussing includes inflammatory conditions, mastitis and abscess mimickers, breast pain, discharge, post-biopsy complications, and presentations related to breast implants. In this review, we are discussing suggestions to close the loop of communication between the emergency radiologist and breast radiologist and to emphasize the importance of the follow-up of the presumed infection.
Mastitis and breast abscess
Mastitis is an inflammatory condition of the breast that may be either infectious or non-infectious in origin.
Puerperal mastitis is the inflammation of the breast during pregnancy or lactation. Infectious mastitis is most commonly an acute presentation, occurring during lactation. It may progress to tissue necrosis and abscess formation. Patients present with erythema of the breast with pain, tenderness, warmth, fever, and leukocytosis. A purulent nipple discharge may be present.[1,2] There are 2–33% of breastfeeding women who may experience lactational mastitis.
Mastitis may also occur in non-lactating patients (nonpuerperal mastitis) secondary to a variety of etiologies. They include periductal mastitis and idiopathic granulomatous mastitis, both of which primarily affect young women. It encompasses all the causes of inflammatory changes in the female breast and mammilla not related to lactation. This inflammation of the breast is often neglected because of the lack of typical clinical signs and symptoms. There is often an underlying duct ectasia or breast cysts, which can rupture, leading to chemical inflammation process rather than an infectious inflammation. Secondary bacterial infection may occur presenting with localized inflammation, pain, redness, and warmth. Mastitis is classified into subareolar and peripheral mastitis.
Non-puerperal subareolar mastitis and abscess are a benign entity often associated with prolonged morbidity. Squamous metaplasia of the ducts leads to keratin accumulation with eventual rupture and leakage of ductal contents into the surrounding breast stroma, resulting in abscess formation. This may be complicated with rupture and the formation of a sinus tract. A recurring subareolar abscess and sinus formation have been referred to as “Zuska’s Disease” or periductal mastitis.
Peripheral breast abscess
Most peripheral breast abscesses are similar to infections elsewhere in the body and are managed similarly. Risk factors would include diabetes, smoking, obesity, or skin conditions such as hidradenitis (clogged sweat glands), acne, or trauma. Furthermore, African-American race is a risk factor.
IMAGING OF MASTITIS AND BREAST ABSCESS
On ultrasound, mastitis usually shows features of cellulitis, skin thickening, subcutaneous edema dilated ducts, heterogeneous tissue, edema, and increased vascularity. Enlargement of lymph nodes should also be expected as a reactive process which should be differentiated from malignant lymph nodes and that can be challenging. 
The sonographic appearance of a breast abscess is similar to abscess formation elsewhere in the body as a hypoechoic complex collection with internal echoes, debris, and some acoustic enhancement and peripheral thick wall and increased vascularity in the surrounding soft tissues [Figure 1].
Mammography can show skin thickening, an asymmetric density, or a mass; these signs are not specific for carcinoma and may reflect only the underlying infection and breast abscess.
The presence of microcalcifications is unusual for mastitis or an abscess. The presence of suspicious microcalcifications is a more specific sign and should warrant a biopsy to rule out carcinoma.
Similarly, unresolved findings such as a mass or an area of sonographic vague shadowing after treatment should also prompt histologic evaluation.
Mammogram should be deferred until after the acute phase subsides. It is recommended to evaluate for cancer especially if patient is over age 40.
MANAGEMENT OF PUERPERAL MASTITIS
The patient should be referred to a lactation specialist, as all patients should receive supportive care (analgesia, ± warm compress, and expression of the milk from the affected breast). Continued breastfeeding should be encouraged in the presence of mastitis and generally does not pose a risk to the infant. Flow of milk would minimize the chances of developing an abscess. If symptoms are not severe or prolonged and in the absence of systemic signs of infection (and/or negative culture), patients may not need further treatment.
If symptoms are severe, prolonged, or in the presence of signs of systemic disease; patients should be treated with antibiotics in accordance with culture results and sensitivities.
MANAGEMENT OF BREAST ABSCESS
This is an area of overlap between specialties and can be directed by the PCP, surgeon, or directly by a breast radiologist, the latter should be able to perform an ultrasound-guided drainage and subscribe antibiotic treatment on an outpatient basis. Empirical oral antibiotic is recommended immediately after aspiration and culture. The best results occur in abscesses smaller than 3 cm. Aspiration should be attempted for the treatment of abscesses of all sizes. Lidocaine is used for local anesthesia before aspiration. The procedure is performed using an 18-gauge needle.
Viscous collections may require a larger gauge needle to completely drain the cavity [Figure 2]. Once emptied, the cavity is flushed with saline 2–3 times until the aspirate appears clear. In abscesses larger than 3 cm, direct instillation of antibiotics into the abscess cavity yields higher success rates.
Using an oblique tract to approach, the cavity helps reduce the incidence of fistula formation. Aspiration and flushing can be repeated if the abscess persists on follow-up ultrasound.
Surgical incision and drainage were the first line of treatment in the past but are now used only after three to five failed aspiration attempts.
FOLLOW-UP RECOMMENDATIONS OF SUSPECTED INFECTION
For routine cases of mastitis, a biopsy is not usually indicated. If symptoms do not fully resolve with supportive treatment and antibiotics, imaging should be pursued to exclude an underlying malignancy or a developing abscess. At our department, we perform a follow-up US in 7–10 days of antibiotics [Figure 3].
Breast abscess follow-up
Puerperal abscesses respond better to treatment than nonpuerperal abscesses, and clinical follow-up after aspiration is usually sufficient.
If there is good clinical response to aspiration and antibiotics, clinical and imaging follow-up with ultrasound is continued every 7–14 days until complete resolution occurs. For atypical presentation, uncertain diagnosis, or a potential complication (e.g., recurrent infection or treatment failure), a biopsy may be warranted.
MASTITIS/ABSCESS MIMICKERS IN EMERGENCY SETTINGS
Infected epidermal inclusion/sebaceous cyst
Epidermal inclusion cysts are thought to arise from the infundibulum of the hair follicle with true epidermis lining and contain keratinous material. They may arise spontaneously or result from a prior trauma. Sebaceous cysts are less common than epidermal inclusion cysts and are not distinguishable from epidermal inclusion cysts on imaging or clinical features.
On mammography, sebaceous cysts appear as circumscribed iso to hyperdense mass. On tangential images, they are contiguous with the dermis. On ultrasound, the epidermal inclusion cyst may appear as a well-circumscribed mass. A characteristic “claw” of dermal tissue that wraps around the margin of the lesion is a good sign to suggest a dermal origin.
Benign and self-limiting, superficial thrombophlebitis: Patients present with pain and cord-like palpable structures. Ultrasound may show a dilated superficial vessel distended with a thrombus or anechoic beaded superficial vein [Figures 6 and 7]. A short-term follow-up should be obtained until resolution.
Galactoceles [Figure 8] are the most common lesions in lactating women. On cessation of breastfeeding, milk may retain and stagnate, causing ductal dilatation and development of cysts or galactoceles. Furthermore, infection is a relatively common complication. Galactoceles may appear sonographically similar to abscesses but would follow a ductal distribution. Diagnosis is made based on the clinical history and aspiration of mixed milky and purulent material from the cyst.
Inflammatory breast cancer
Patients with inflammatory breast cancer have rapid onset of symptoms. Breast erythema and edema, often with no palpable mass, typically may involve one-third or more of the breast. Histopathologically, it is an invasive carcinoma.
Inflammatory cancer should be carefully distinguished from mastitis. Diagnostic features include a rapid onset of erythema (redness) involving one-third or more of the breast [Figure 9], edema (swelling), an orange peel appearance (ridged or pitted skin), and/or abnormal breast warmth, with or without a lump that can be felt. There are symptoms that mimic inflammation, but there is no true inflammatory component to inflammatory breast cancer. Usually patients have less pain, skin thickening more diffuse.
If there is no response or an incomplete response to antibiotic treatment within 1–2 weeks, malignancy such as IBC should be considered. A biopsy should be performed by the breast radiologist.
The typical mammographic appearance of inflammatory breast cancer includes diffuse enlargement of the breast, increased trabeculation, asymmetrical diffuse increased density [Figures 10,11,12,13 and 14], skin thickening, and enlarged lymph nodes.
The breast radiologist should communicate results with the patient and insure communication with the referring physician or the breast surgeon.
OTHER EMERGENCY CONDITIONS
Breast localized thickening or pain
A common presentation is breast pain, thickening or both are seen in young women with no sonographic correlate. At our practice, if the presentation is a lump or thickening in a young woman with a negative ultrasound, we recommend a follow-up examination in 3 or 6 months and possible biopsy if the palpable abnormality persists.
According to ACR appropriateness criteria, if pain is non-cyclical, or focal breast pain, the ACR suggests the following. Women less than 30 years of age, ultrasound should be performed first and mammography may be indicated in patients under 30 when a suspicious lesion is found on ultrasound. In the 30–39-year-old age group, adding mammography is appropriate. Mammography should be performed with ultrasound in patients age 40 and older or in a patient of any age who would normally qualify for a mammogram.
Nipple discharge is of concern if it is bloody, serous, red, pink, brown or clear, spontaneous, persistent, or unilateral. Workup should include ultrasound, mammogram, and ductogram of any unilateral discharge [Figures 15 and 16]. This discussion is beyond the scope of our review, and patients should be referred to the breast clinic.
Biopsy with a core needle during lactation can be unavoidable and milk fistula can occur [Figure 17]. Management of milk fistula is mainly conservative, as it often resolves spontaneously and some cases may need cessation of breastfeeding and bromocriptine may be needed.
Post-biopsy hemorrhage or pseudoaneurysm
Post-biopsy hematoma is not uncommon and to achieve hemostasis, manual compression after biopsy is usually performed. At mammogram, hematoma appears as a new density at the biopsy site [Figure 18]. At ultrasound, hematoma may show a new hypoechoic collection at the biopsy site [Figure 19]. Hematomas after core biopsy can be avoided or minimized by manual compression, and administration of lidocaine with epinephrine. A compression bandage may also be applied across the breast for a few hours or overnight to ensure continued hemostasis.
An observation for 30 min before discharge is preferred in our practice. Surgical intervention is rarely needed to stop the bleeder.
A pseudoaneurysm is basically a hematoma that communicates with the arterial lumen. On mammography, a circumscribed mass adjacent to a blood vessel can be seen. Ultrasound may show pulsating anechoic lesions, to-and-fro Doppler pattern. Management options for pseudoaneurysm include surgical repair, sonographically guided compression therapy, percutaneous thrombin or alcohol injection, and coil embolization.
Dixon and Khan suggested using ultrasound to monitor pseudoaneurysm may negate the need for invasive treatment. El Khoury et al. suggested that radiological treatments are more successful than sonographically guided compression and surgery, and that simple monitoring may offer the chance of spontaneous occlusion without the need for invasive intervention.[21,22]
Presentations related to breast implants
Chest trauma and implant rupture
Trauma of the breast can present with a lump due to hematoma, blistering, or ulceration. On mammogram, a band-like density can be seen which would evolve into fat necrosis and oil cysts later. Proper evaluation of a silicone implant rupture should include ultrasound and MRI.
Traumatic rupture of a breast silicone implant may be noticed on the initial chest CT scan performed as a part of the initial trauma series and should be addressed in the report for surgical consultation [Figure 20].
FDA recommends that patients with silicone breast implants should receive MRI screening for a “silent rupture” 3 years after the initial implant surgery and every 2 years after that.
POST-IMPLANT SURGERY COMPLICATION
Post-implant surgery hematoma is rare, if large it may present to the emergency department and may need evacuation/ surgical intervention. Diabetes, obesity, older age (>65 years) and nicotine use, and the presence of a large seroma increase the risk of post-operative infection. For any suspicion of infection, a drainage should be obtained and sent to microbiology.
A post-surgical infection may be complicated by abscess formation, usually within 1–2 weeks after surgery, presenting as a fluctuant tender mass at the surgical site.
Ultrasound is the first modality used for evaluation. Ultrasound appearance of cellulitis may appear as edema with linear hypo or anechoic fluid interspersed between fat lobules of the breast. This may be indistinguishable from normal post-operative appearance; clinical correlation is important. The appearance of infected seroma on ultrasound ranges from an anechoic fluid collection to a heterogeneous complex fluid collection [Figures 21 and 22]. In infected seroma, debris and hypervascularity may be key to detect a drainable infected collection.
Emergency radiologist awareness of common breast presentations in the ED is very important. The main presentations are infection in lactating and nonlactating women including mastitis, cellulitis, or chronic granulomatous mastitis. Evaluation of an abscess and drainage may provide immediate relief
Inflammatory cancer may mimic infection and differentiation is very important. Follow-up in the breast clinic after a course of antibiotic treatment is the best way to deal with this possibility
Mondor’s disease is an easily missed diagnosis given its rarity. Follow-up in the non-emergency clinic is appropriate
Biopsy of a mass in a lactating woman may lead to milk fistula. However, if the finding is suspicious, biopsy recommendation should always be made regardless of this possibility. This is usually referred to the breast clinic
Identification of ruptured breast implants on CT should always be kept in mind
Patients present with pain or discharge in the ED are quite common. If ultrasound is negative for mass, a follow-up mammogram on non-emergent basis would be reasonable.
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Conflicts of interest
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