Teaching Case

A 61-year-old woman presented with a painful and redness left breast with nipple retraction and a palpable central hardening mass in the left breast. Left axillary lymph nodes were also palpable. The patient was a cigarette smoker and had a previous mastitis episode of left breast.

The initial sonogram revealed a hypoechoic left retro-areolar lesion with thick liquid content and thickening of the areolar cutaneous planes, suggesting a retro-areolar abscess (fig. 1).

Axial T1 (fig. 2) and T2-weighted (fig. 3) MR images showed a thickened wall cystic lesion in the subareolar region of left breast. Axial early phase post-contrast T1-weighted MR images (fig. 4) demonstrate a retro-areolar collection with early rim-enhancing in left breast (white arrow), with washout on late-phase post-contrast axial (fig. 5) and sagittal T1 weighted MR images (fig. 6). Ultrasound-guided biopsy was performed to rule out malignancy. Histologic examination reveals fragments of breast tissue with polymorphic inflammatory infiltrate and formation of granulation tissue, identifying keratinous scales. The findings described were considered compatible with the clinical-imaging hypothesis of a retro areolar abscess / Zuska's disease.

Zuska breast disease is clinical term used to describe an uncommon condition of a recurring periareolar non-puerperal abscess associated with fistula tracts. It affects young women and it is strongly related to cigarette smoking. This type of abscess is becoming more frequent due to the increasing use of tobacco [1,2].

Smoking may have a direct toxic effect on the epithelium of the retroareolar lactiferious ducts, resulting in squamous metaplasia and proliferation of the epithelium, leading to formation of keratin plugs and central acute cellular inflammatory infiltrates. This results in the obstruction and dilatation of the ducts, leading to abscess formation and often with development of cutaneous fistulas extending to the periareolar region. Secondary bacterial infection may occur, usually caused by Staphylococcus bacteria. [3,4,5].

Pain, redness and heat are common clinical symptoms of breast abscess. Fever is uncommon [1]. Palpable masses are not rare and are frequently associated with skin erythema. At palpation these masses are poorly defined and can lead to nipple retraction, which raises worry about malignancy [5]. Cutaneous fistulas formation occur in one-third of patients [2].

When abscess is suspected, mainly in the setting of a palpable mass, US should be the first-line exam. Ultrasound findings include a complex cystic lesion or a heterogeneously hypoechoic mass around the nipple [3,5]. Whenever possible, it is suggested that mammography should be delayed until the resolution of the acute episode, mainly for patient comfort. Mammographic findings include an ill-defined mass, focal asymmetry or even normal findings. The main differential diagnosis is inflammatory breast cancer and MR imaging can be useful in differentiating it from a breast abscess, although both may exhibit similar radiological features such as mass lesion or a non-mass area of enhancement [3,6]. There are however differences in the enhancement pattern. Masses in inflammatory cancer tend to have greater initial enhancement and subsequent washout. Lesions in mastitis tend to show a more persistent or plateaued enhancement pattern [5,7].

Patients with mastitis that do not respond to antibiotic therapy should undergo biopsy [4,7].

Retroareolar nonpuerperal abscesses are associated with a chronic and recurrent clinical course, with longer treatments and often require multiple drainage or surgical procedures [2,5].

Ultrasound-guided drainage with antibiotic therapy has been found effective in the treatment. Smoking cessation should be strongly encouraged to prevent recurrences since it’s the most significant factor associated with recurrence [2,5].

The role of the radiologist is essential to characterize these collections and to perform percutaneous drainage and follow-up.