Granulomatous mastitis (GM) is a rare, chronic inflammatory breast condition of unknown aetiology. The clinical presentation, diagnosis, treatment and emerging therapies of granulomatous mastitis are elucidated in this article. 

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Granulomatous Mastitis (GM)

Granulomatous mastitis (GM) typically affects women of childbearing age and can sometimes pose a diagnostic challenge due to its ability to mimic breast cancer or infectious mastitis typically presenting as breast abscess with surrounding doughiness in a non-lactating woman, generally around 6 to 8 years after the last pregnancy. 

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Clinical presentation

The clinical presentation of GM is variable. Common symptoms include:

• A firm, palpable breast mass, often poorly defined but warm to touch
• Breast pain
• Skin redness or inflammation
• Skin thickening or dimpling
• Nipple discharge or retraction
• Abscesses, one or more or fistula formation (in advanced cases)

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Diagnosis

GM diagnosis hinges on careful evaluation, including:

1. Imaging: Mammograms and ultrasounds often show irregular or ill-defined masses that may raise suspicion of malignancy.
2. Core Needle Biopsy: The gold standard for diagnosis. Biopsy reveals hallmark features of non-caseating granulomas, multinucleated giant cells, and a mixed inflammatory infiltrate.FNAC has no role in differentiating breast diseases.
3. Microbial Studies: A culture of pus from an abscess is necessary to rule out infectious causes such as tuberculosis and fungal infections and rule out superadded bacterial infection.

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Differential diagnoses

Several conditions must be considered and excluded before settling on a GM diagnosis:

1. Breast cancer: The most critical differential diagnosis to be ruled out on tru-cut biopsy.
2. Infectious Mastitis: Bacterial, fungal, and mycobacterial infections should be excluded.
3. Lymphoma of the breast is a rare presentation though.
4. Wegener's Granulomatosis: A systemic vasculitis that may cause breast lesions.

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Treatment 

The optimal treatment for GM remains an area of debate, but several modalities have proven beneficial:

1. Observation: In mild cases, especially where there's a high suspicion of a self-limiting process, watchful waiting may be appropriate. However, close follow-up is needed for proper counselling and explaining the self-limiting nature of the disease and chances of recurrence with multiple surgeries if aggressive need to be explained to the patient and relatives
2. Corticosteroids: Oral Prednisone or other systemic corticosteroids are often considered first-line therapy due to their anti-inflammatory effects. Treatment duration and tapering schedules can vary. Always should be combined with antibiotics for better results. Some people have tried intralesional steroids but no studies are backing it at present.
3. Antibiotics: Although GM is not primarily an infectious disease, antibiotics may be used adjunctively in cases with suspected concurrent bacterial infection or abscess formation. Generally preferred ones are doxycycline, clarithromycin(As for atypical mycobacterial agent) etc, which can be given for a few weeks at a time.
4. Methotrexate: This immunosuppressive drug is an alternative for patients who fail to respond to corticosteroids or who experience significant steroid side effects.
5. Antiestrogen
6. Surgery: Surgical intervention may be necessary in various scenarios:

• Diagnostic Excisions: If the diagnosis is uncertain even after biopsy.
• Drainage of Abscesses: To provide relief and reduce the risk of fistula formation. Ideally should be USG-guided if facilities are available.
• Wide Local Excision: For extensive or recurrent disease that doesn't respond to conservative management. It needs to include excision till nipple-areola complex sparing skin but removing all sub-cut breast tissues/ducts as it could be the cause of recurrence.

7. Other Immunosuppressants: Drugs like azathioprine have potential uses but require further study.

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Challenges and considerations

Several challenges exist in the management of GM:

1. Lack of standardised treatment protocols: Treatment approaches can be inconsistent, with variations in medication choice, duration, and surgical indications.
2. Recurrence: GM can be a recurrent condition, even after seemingly successful initial treatment. As the aetiology is not known it's considered idiopathic.
3. Cosmetic concerns: Surgical excision and fistulisation may lead to breast asymmetry or scarring. Sometimes physically and mentally mutilate the patient.
4. Psychological impact: Due to its resemblance to cancer, the prolonged diagnostic process and uncertain outcomes and recurrence can cause significant distress for patients. It may lead to incompliance.

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Emerging therapies and future research directions

Ongoing research focuses on:

1. Prolactin-lowering medications: Studies suggest a potential role for bromocriptine or cabergoline in preventing GM recurrence.
2. Targeted biologics: New biologic therapies targeting specific immune pathways may hold promise for the future.

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Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr Alpa Modi, MS(Gen Surg) is a practising surgeon from Thane.