Effect of Steroids on Granulomatous and Non-granulomatous Mastitis: A Case Series of 12 Patients

TL;DR

A study of 12 patients found that steroids effectively reduced breast inflammation, even when granulomatous mastitis wasn't confirmed.

Contribution

The study suggests steroids can be effective for suspected granulomatous mastitis without requiring a biopsy confirmation.

Findings

All patients showed improvement with corticosteroids, including those without confirmed granulomas.

Combination therapy with steroids and methotrexate helped prevent relapse during steroid tapering.

Microbiological tests were negative, supporting a non-infectious cause for the inflammation.

Abstract

Background and objective: Granulomatous mastitis (GM) is a rare, chronic inflammatory breast condition characterized by granulomatous changes around the lobules and ducts, typically presenting as a unilateral, tender, swollen, and erythematous breast. First described in 1972, its exact cause remains unclear, and there is no standardized first-line treatment. Corticosteroids are commonly used with generally positive outcomes, though they carry risks of side effects and relapse. In a case series of 12 patients with GM-like symptoms, six were confirmed histologically, and all showed improvement with corticosteroids. Diagnosis relies on biopsy, which reveals non-necrotizing granulomas and immune cell infiltration. As GM often mimics bacterial mastitis but is usually sterile, antibiotics are frequently ineffective. In steroid-intolerant or relapsing cases, low-dose methotrexate is a potential alternative, though it has notable side effects.

Materials and methods: For this analysis, patient data from 2022 were retrospectively collected from an electronic medical database, focusing on women aged 18-70 residing in the UAE who presented with breast lumps or pain. Exclusion criteria included pregnancy, male gender, and non-residents of the UAE, as these patients would not be able to attend follow-up consultations to assess treatment effectiveness. Information such as age, marital status, presence of children, presenting symptoms, surgical interventions, medications (antibiotics, steroids, methotrexate, azathioprine), insulin resistance, and biopsy findings were recorded. Biopsies (core needle, excisional, or post-surgical) were reviewed by a pathologist and stained using Ziehl-Neelsen, H&E, and PAS techniques to confirm granulomas. Of 12 patients, six had biopsy-confirmed GM, and 11 were treated with steroids (one opted for observation only). Follow-up included tracking remission, progression, and treatment response. Statistical analysis involved presenting continuous variables such as age as mean ± SD and categorical variables as counts and percentages, with key findings reported with 95% confidence intervals.

Results: This study included 12 married women aged 31 to 45 years (mean age 38.5±4.9 years) treated for granulomatous mastitis. Half (six of 12) had biopsy-confirmed granulomas, while 92% received steroids and 58.3% were treated with methotrexate. Breast abscess was the most common presenting complaint (66.7%), followed by breast mass and mastitis. Co-morbidities were present in 58.3%, with 41.7% showing insulin resistance. All microbiological tests, including cultures and TB screening, were negative. Among the six granuloma-positive patients, five received both steroids and methotrexate. Interestingly, even granuloma-negative patients who received this combination showed similar improvement. One patient who refused steroid treatment continued to relapse. Those treated with steroids showed good clinical and radiological response, with tapering over time. Seven patients who relapsed during steroid tapering were started on methotrexate with low-dose steroids, followed by gradual weaning. All patients responded well and remained symptom-free at six-month follow-up.

Conclusion: This study suggests empiric corticosteroid therapy may be effective for managing recurrent breast inflammation, even without biopsy-confirmed granulomatous mastitis. Both confirmed and suspected cases showed similar outcomes.

Figures