Granulomatous mastitis

Section: Breast Curriculum: Curriculum, page 10

The Breast Journal - 2024 - Dilaveri - Idiopathic Granulomatous Mastitis, page 1

Definition

• Rare, benign, chronic non-caseating inflammatory breast disease

Incidence

• Most young parous women of child-bearing age (< 50)
• Post-partum (few months – 8 years)
• South east Asian and middle eastern

Classification

• Primary (or Idiopathic granulomatous mastitis)
• Secondary
  • Systemic granulomatous disease e.g. Sarcoidosis, Wegener’s Granulomatosis
  • Granulomatous infection – e.g. Tuberculosis, Histoplasmosis

Aetiology of Primary Disease

• Essentially unknown
  • It is thought to start with milk stasis and which triggers an autoimmune reaction
  • This seems to be modulated by Corynebacterium species
• Smoking not associated

Clinical

• Usually unilateral + peripheral, firm irregular mass
• Occur all quadrants, except for subareolar
• Mimic malignant tumours in terms of physical signs & mammographic findings
• May grow rapidly

Pathology

• Granulomas involving Lobular Epithelium
• PMNs, Epithelioid Cells, Plasma Cells, Giant Cells (Langhans or foreign body type)

Investigaitons

• FNA / Core / Excisional Bx required for Dx → Tissue for culture
• Consider Mantoux, CXR, Histoplasmosis serology

Management

• Drainage of sepsis
  • I&D or aspiration
• Antibiotics
  • Usually Doxycycline or Augmentin
• Can consider
  • Doxycycline 3 months
  • Steroids
    • Steroids improve sx initially but condition worsens with dose reduction
      • Can be used in persistent or recurrent disease
  • Methotrexate and Azathioprine
• Excision if non-responsive
  • May require Mastectomy
  • Do not recommended local excision as often results on chronic non-healing wound

Prognosis

• Mostly resolves over 6–12-month period *** Dr Rapson - 12-18months. Fluctuating course.
• Long-term follow-up advised