CASE 6 Woman with painful periareolar mass
A 42-year-old perimenopausal woman describes having pain near the nipple of her right breast. She is a smoker and has no history of breast cancer in her family. Examination demonstrates a palpable, erythematous, painful, 3-cm periareolar fluctuant mass.
Nonpuerperal periareolar abscess
Appropriate initial imaging for this 42-year-old patient with focal pain is a diagnostic mammogram, which showed skin thickening and a retroareolar mass (FIGURE 6a). Further evaluation with targeted ultrasound showed a thick-walled anechoic collection with echoes compatible with an abscess (FIGURE 6b).
Art Credit: Images courtesy of Leigh Neumayer, MD, MS, MBA
Mammographic findings in a patient with mastitis may be normal or demonstrate skin and trabecular thickening. Ultrasound imaging may show dilated ducts and heterogeneous tissue secondary to inflammation and edema without a discrete fluid collection. In cases with breast abscess, in addition to the mammographic findings described above, a mass, or an asymmetry, may be seen, most commonly in a subareolar location. On ultrasound, a hypoechoic collection with mobile debris, no internal flow on Doppler, and thick hypervascular walls can be seen with abscess, occasionally giving the appearance of a complicated cyst or a mixed cystic, solid mass.
The most important differential for mastitis is inflammatory breast cancer. Most cancers appear solid but can have central necrosis, mimicking a complicated cystic mass on ultrasound. The location for mastitis or abscess is most frequently subareolar. The presence of microcalcifications in a mass indicates the possibility of cancer.
Contrast-enhanced MRI can be helpful to differentiate between infection and cancer, with cancers showing initial early enhancement and washout kinetics compared with infected collections that show no enhancement or peripheral enhancement with a plateau or persistent enhancement curves. When clinical and imaging findings are unchanged after treatment of mastitis and abscesses, a core needle biopsy should be performed.21,22
There are 2 categories of mastitis and breast abscess: lactational and nonpuerperal (all mastitis that occurs outside the lactational period). The World Health Organization definition of puerperal mastitis includes pain, local redness, warmth and swelling of the breast (usually unilateral), fever, and malaise.4 Concerning etiology, epithelial lesions in the nipple area caused by breastfeeding can allow pathogens to enter and cause infection. The most common microorganism is Staphylococcus aureus.4 Continued emptying of the breast is important, combined with early antibiotic therapy (dicloxacillin is often the first line; if the patient is penicillin allergic, use a macrolide such as clindamycin). If no improvement is seen in 48 to 72 hours, imaging should be performed.
In most cases, continuation of breastfeeding is possible. If mastitis has evolved into an abscess in a lactating woman, it can be aspirated under ultrasound guidance. Incision and drainage should be avoided unless the abscess persists after multiple aspiration attempts, it is large, or if the overlying skin is thin or otherwise appears nonviable.
Nonpuerperal mastitis includes peripheral, periductal, and idiopathic granulomatous mastitis (IGM). Peripheral mastitis behaves like infections/abscesses in other soft tissues, responds well to treatment (antibiotics and percutaneous drainage), and is less likely to recur than periductal mastitis and IGM.21,23
Periductal mastitis and abscess, also known as Zuska disease, has a pathogenesis distinct from other forms of mastitis. Squamous metaplasia of the usual cuboidal epithelium of the breast ducts leads to keratin plugging that can cause infection.23 Risk factors include obesity, smoking, and macromastia. The typical presentation of Zuska disease is a woman with a history of chronic smoking and/or a congenital cleft in the central nipple.23 Periareolar signs of inflammation (redness, swelling, warmth) may be accompanied by an abscess. These can recur and lead to chronic fistula formation, especially if there is a history of intervention (such as aspiration, incision, and drainage).
Treatment of Zuska disease includes symptom relief and antibiotics. If S aureus is present, infection with methicillin-resistant S aureus is likely, and treatment with clindamycin or amoxicillin/clavulanic acid is preferred. If abscess is present, aspiration (preferred, often under ultrasound guidance) or incision and drainage (if the skin is compromised) may be required. If disease is recurrent or associated with a chronically draining fistula, surgical intervention may be warranted, in which resolution requires removing the keratin-plugged ducts in and immediately below the central core of the nipple. Given the association between Zuska disease and smoking, cessation should be encouraged, although there is no guarantee that this will resolve the issue.23
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