A breast abscess is a relatively rare but significant complication of mastitis that may occur during breast-feeding, particularly in primiparous women. The clinical context is a key to diagnosis as imaging appearances (particularly ultrasound) can mimic many other entities such as breast carcinoma. Rubor, calor, dolor, functio lysa.
Breast abscesses are thought to develop in 5 - 11% of lactating women with infectious mastitis 3. In this context they are also referred to as lactational abscesses.
There is often an antecedent clinical history of mastitis. The breast usually appears hot, red and indurated. The course may be affected by antibiotic therapy depending on when the patient is imaged.
A breast abscess is defined as an inflammatory mass that drains purulent material either spontaneous or on incision. The predominant infectious organism is Staphylococcus aureus, and often is the penicillinase-producing type. Other common types include Staphylococcus epidermidis and Proteus mirabilis.
Peripheral breast abscesses have generally been associated with mastitis during breast feeding, but previous reports indicate that abscesses are common among non-lactating women.
- increased incidence in those with diabetes
The clinical context is crucial to image interpretation.
Ultrasound is considered the most useful initial imaging modality when a breast abscess is suspected. It is also the imaging method of choice to monitor progress, response to therapy and to ensure resolution.
Aspiration of a breast abcess is easily and quickly performed under ultrasound guidance and the patients are immensely grateful for the symptomatic relief. These are some of the most grateful patients in medicine.
The ultrasound appearance of an abcess in the breast is protean but may be typically seen as a irregular hypo-echoic breast lesion with varying degrees of definition. Sonographic that suggestive of a breast abscess include
- adjacent interstitial fluid 9
- presence of a hypo-echoic rim 9
Mammography is vary rarely indicated or useful. Mammographic appearances are often non specific and in the age group where breast abscesses are most often found, mammography is rarely done. It adds radiation but not information in this group of patients. Where resolution is incomplete or there are clinical concerns about the diagnosis, mammography may be indicated on a case to case basis.
Treatment and prognosis
Mastitis and some abscesses may respond to antibiotic treatment with aspiration if needed. Unfortunately, even with adequate treatment, a significant proportion of breast abscesses recur, especially the non-puerperal abscesses 10.
Breast feeding from the affected breast should cease until resolution is complete.
On ultrasound a breast abscess can easily mimic other entities such as a breast malignancy or a breast haematoma on imaging grounds alone. In practice, the most difficult differentiation is from a galactocoel. The lesions occur in the same cohort and the imaging characteristics are very similar to a galactocoel. Clinical differentiation is key. Be very weary of lesions that enlarge or lesions that look like an abcess but are not painful or warm to the touch. Carcinomas can be estrogen receptive and can grow very significantly in pregnancy. Not all lesions found in pregnancy and lactation can simply be assumed to be an abcess or galactocoel. Tread wearily with lesions that do not resolve or that linger. Close follow up is indicated.
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- 10. Eurorad teaching files : Case 8841
Synonyms & Alternative Spellings
|Synonyms or Alternative Spelling||Include in Listings?|
|Pyogenic breast abscess||✗|