Breast abscess

Section: Breast Curriculum: Curriculum, page 10

Definition

• Abscess (collection of encapsulated pus (dead neutrophils)) within breast tissue

Incidence

• Seen in 5-10% of lactating women with mastitis
• Classification
• Lactational vs Non-lactational

Aetiology & Pathology

• Lactational
  • Trauma: Cracked nipples → bacterial entry
    • Occur in the first 1-2 weeks after delivery (inexperienced mother) and
    • At ≈ 6 months, when the child develops teeth
  • Stasis / engorgement
    • Often occurs at time of weaning
• Non-lactational
  • Usually occurs as a manifestation of Mammary duct ectasia/ Periductal Mastitis
  • Underlying pathophysiology: plugging of the duct (by mucus / keratin) → Dilatation → Secondary infection

Clinical

• Location
  • Lactational abscesses tend to be deep/peripheral
  • Non-lactational periareolar
• Pain, tenderness, lump ± systemic unwellness

Pathology

• Lactational: S. aureus = commonest bacteria
• Non-lactational abscesses: Staph / Strep / mixed / anaerobes

Investigations

FBC ± diagnostic USS or aspirate, if required

Management

• Lactational
  • Antibiotics - Flucloxacillin (Staph/Strep)
  • Aspirate
    • Can have repeated USS-guided aspiration or USS-guided drain placement
  • Avoid incision, if possible (due to fistula risk)
  • Woman should continue breast-feeding
  • Follow-up
• Non-lactational:
  • Antibiotics - Augmentin (Staph / Strep / mixed / anaerobes)
  • Aspirate or I+D
    • ± Cavity Bx / investigate for Ca / underlying cause
  • Advise pt to stop smoking

Prognosis / Natural Hx:

• If undrained → may burst through skin (if skin is compromised or thin don’t bother with aspiration)
• If drained → Up to 50% recur or form a mammary duct fistula (or galactocoele)

Follow-up

• If abscess has been aspirated: F/up clinically +/- with repeat USS in ≈ 3/7
• F/up USS & mammogram for all non-lactational breast abscesses in > 35yo?