What is the treatment for idiopathic granular mastitis?

Treatment of Idiopathic Granulomatous Mastitis

The first-line treatment for idiopathic granulomatous mastitis (IGM) is systemic corticosteroids, typically starting with prednisone 0.5-1 mg/kg/day, with the addition of a steroid-sparing agent such as methotrexate for patients with severe disease or to prevent recurrence. 1, 2

Diagnostic Confirmation

• IGM is a rare benign inflammatory breast condition that must be confirmed histologically by the presence of non-caseating granulomatous inflammation centered on breast lobules 1
• Diagnosis requires exclusion of other causes of granulomatous inflammation through tissue staining, cultures, and PCR testing 1
• IGM typically affects young women of reproductive age (25-40 years) 2

Treatment Algorithm

First-line Treatment:

• Corticosteroid Therapy:
  • Initiate prednisone at 0.5-1 mg/kg/day (typically 60-80 mg/day) 3, 2
  • Continue for 2-4 weeks at full dose, then begin tapering based on clinical response 3
  • Tapering schedule: decrease by 10 mg every 2 weeks until reaching 30 mg/day, then 5 mg every 2 weeks until 20 mg/day, followed by 2.5 mg every 2 weeks until completed 3
  • Good clinical response is typically observed with this regimen 2

For Refractory Cases or Steroid-Dependent Disease:

• Add Steroid-Sparing Agents:
  • Methotrexate is the preferred agent, used in up to 54.5% of IGM cases 1
  • Start methotrexate at 15-25 mg weekly 3, 1
  • Consider azathioprine or mycophenolate mofetil as alternatives 3

Surgical Management:

• Limited role in primary management due to high recurrence rates 4
• Consider for drainage of abscesses or removal of residual masses after medical therapy 1
• Complete excision is not recommended as first-line treatment due to risk of poor cosmetic outcomes and recurrence 2, 4

Antibiotic Therapy:

• Only indicated if secondary bacterial infection is present 5
• Some cases may involve Corynebacteria, which might benefit from targeted antibiotic therapy 5

Monitoring and Follow-up

• Regular clinical assessment of breast masses, pain, and inflammatory signs 1
• Monitor for adverse effects of medications:
  • Corticosteroids: hyperglycemia, weight gain, osteoporosis, mood changes 3
  • Methotrexate: hepatotoxicity, bone marrow suppression, gastrointestinal symptoms 3
• Bone health monitoring with calcium and vitamin D supplementation for patients on prolonged corticosteroid therapy 3
• Follow patients for recurrence, which occurs in approximately 13.6% of cases 1

Treatment Duration and Outcomes

• Most patients (72.7%) can discontinue treatment with acceptable disease control 1
• Treatment duration typically ranges from 3-6 months but may be longer in refractory cases 1, 2
• Some patients may require maintenance therapy with low-dose corticosteroids or methotrexate to prevent recurrence 2

Special Considerations

• Pregnancy and lactation may exacerbate the condition, as hormonal factors are suspected triggers 5
• Avoid unnecessary biopsies once diagnosis is established, as they may worsen inflammation 4
• Consider non-steroidal anti-inflammatory drugs for mild cases or as adjunctive therapy 4
• For severe cases with extensive involvement, consider pulse methylprednisolone therapy before transitioning to oral corticosteroids 3

Early recognition and appropriate treatment of IGM can prevent unnecessary surgical interventions and improve quality of life for affected patients 2, 4.