https://orcid.org/0000-0003-4117-6603
An exhaustive narrative review on idiopathic granulomatous mastitis (IGM) has been recently published in Journal of Investigative Surgery. IGM is a rare benign inflammatory breast disease characterized by non-caseating granulomas and micro abscess formation centered on the breast lobules. It has been estimated that IGM can be detected in 0.4-1.6% of all breast biopsy specimens.Citation1
This narrative review aims to give the reader an accurate overview of the etiology, clinical presentation, diagnosis, and treatment of IGM.Citation2 The authors of this review should be thanked, as, despite not performing a systematic research, they succeed in summarizing the heterogeneous data on IGM present in the current literature.
Until now, the etiology of IGM remains controversial;Citation3 it has been hypothesized that this chronic breast disease may be linked to multiple predisposing factors, such as the use of contraceptive pills, high level of prolactin, smoking, and alpha-1 antitrypsin deficiency.Citation4 Notably, an autoimmune reaction due to presence of milk proteins in the interstitial breast tissues, as a consequence of micro-trauma secondary to trauma, chemical irritation, and infection seems to be the most accredited pathogenetic hypothesis for explaining this disease.Citation5 In support of this, it should be underscored that the diagnosis of IGM tends to occur within five years after pregnancy in patients between 30 and 40 years who have undergone breastfeeding. Overall, an autoimmune reaction has been considered deeply involved in IGM pathogenesis, considering that this disease IGM responds well to immunomodulators like steroids and methotrexate (MTX).
A monolateral mass soft in texture, sometimes characterized by overlying skin erythema, orange peel-like skin changes, and even nipple inversion can be the clinical presentation of IGM; nevertheless, the diagnosis of IGM may be challenging, as it frequently must be distinguished from breast cancer.
For this purpose, mammography, ultrasound and magnetic resonance imaging are useful but not definitive diagnostic tools, and a tissue biopsy may be necessary to confirm the presence of disease.Citation6
Currently, there is no consensus regarding the best therapy for patients affected by IGM. Numerous therapeutic options are available, including observation, antibiotics, surgery, or drug therapy (steroids and immunosuppressants).Citation7 Generally, observation can be reasonably adopted in mild cases; antibiotics have very limited efficacy. The effectiveness of steroids has long been reported, and their topical formulations have demonstrated potential as a first-line option as they balance good efficacy with limited side effects. Surgical excision and MTX, or combination of them, are often adopted in patients with recurrence or steroids failure. Notably, a recent meta-analysis showed that managing IGM with only steroids may be less effective than the combination of steroids and surgery.Citation8 Other potential indications for surgical intervention include diagnostic biopsy, drainage of an abscess, and excision of complex fistulas.
In the last years, an algorithm differentiating treatments (expectant management, surgical excision, use of steroid and/or MTX) according to the extension and severity of the pathology has been proposed;Citation9 nevertheless, at the moment, the therapeutic management of patients with IGM remains worldwide divergent.
In conclusion, it is of extreme importance to summarize the heterogenous evidence related to IGM to improve the diagnosis and treatment of patients affected. In this context, the exhaustive contents of this narrative review will help the reader to understand the limited data that have been emerged from the current literature until now. In the near future, new original research studies are needed to draw a conclusion of the pathogenesis, best diagnostic and therapeutic option for patients affected by IGM.
Disclosure statement
No potential conflict of interest was reported by the author(s).
References
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- Yin Y, Liu X, Meng Q, Han X, Zhang H, Lv Y. Idiopathic granulomatous mastitis: etiology, clinical manifestation, diagnosis and treatment. J Invest Surg. In press. doi:https://doi.org/10.1080/08941939.2021.1894516.
- Altieri M, Barra F, Casabona F, Soriero D, Gustavino C, Ferrero S. Idiopathic granulomatous mastitis: etiopathogenetic considerations on a rare benign inflammatory breast disease. J Invest Surg. 2020;1–2 doi:https://doi.org/10.1080/08941939.2020.1742403.
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- Godazandeh G, Shojaee L, Alizadeh-Navaei R, Hessami A. Corticosteroids in idiopathic granulomatous mastitis: a systematic review and meta-analysis. Surg Today. 2021. doi:https://doi.org/10.1007/s00595-021-02234-4.
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