Clinical Practice Guidelines for Diagnosis and Treatment of Patients with Non-Puerperal Mastitis: Chinese Society of Breast Surgery (CSBrS) Practice Guideline 2021
Non-puerperal mastitis (NPM) refers to a group of benign breast diseases that occur in non-puerperal women, characterized by inflammation and infection of the breast tissue outside the postpartum period. The primary pathological types of NPM include periductal mastitis (PDM) and granulomatous lobular mastitis (GLM). These conditions are often associated with breast masses, abscesses, and, in later stages, the formation of fistulas, sinuses, or ulcers. The natural course of NPM is typically prolonged, lasting between 9 to 12 months, with a high tendency for recurrence. Due to the lack of standardized treatment protocols, the Chinese Society of Breast Surgery (CSBrS) has developed clinical practice guidelines to assist clinicians in diagnosing and managing NPM effectively. This article provides a comprehensive overview of the 2021 CSBrS guidelines, covering diagnostic methods, pharmacotherapy, surgical interventions, and expert recommendations.
Diagnosis of Non-Puerperal Mastitis
Accurate diagnosis is critical for the effective management of NPM. The guidelines emphasize the importance of clinical evaluation, imaging, and pathological examination to differentiate NPM from other breast conditions, such as breast tuberculosis or specific granulomatous lesions.
1.1 Diagnostic Methods
The following diagnostic methods are recommended for NPM:
1.1.1 Ultrasound
Breast ultrasound is the preferred imaging modality for evaluating NPM. It provides detailed information about the characteristics of the lesion, the presence of abscesses, and their extent. Ultrasound is particularly useful for distinguishing between PDM and GLM, as well as for guiding interventions such as needle aspiration or biopsy. The guidelines assign a Level I evidence and Strength of Recommendation A to ultrasound as a diagnostic tool.
1.1.2 Detection of Pathogenic Microorganisms
Identifying pathogenic microorganisms is essential, especially in cases of acute inflammation or abscess formation. Microbiological testing, including bacterial culture and DNA sequencing, can help determine the causative agents and guide antibiotic therapy. This method is supported by Level II evidence and Strength of Recommendation A.
1.1.3 Pathological Diagnosis
Pathological examination remains the gold standard for diagnosing NPM. Microscopic analysis of hematoxylin and eosin-stained tissue sections can reveal characteristic features of PDM and GLM. PDM is characterized by dilated ducts filled with pink material, fatty acid crystals, and infiltration of lymphocytes, plasma cells, and neutrophils around the ducts. GLM, on the other hand, presents as multifocal non-caseating granulomas centered on lobular units, composed of epithelioid cells, Langhans giant cells, neutrophils, and lymphocytes, often accompanied by microabscesses. Pathological diagnosis is assigned Level I evidence and Strength of Recommendation A.
1.2 Type of Biopsy
The guidelines recommend specific biopsy techniques for obtaining tissue samples for pathological examination:
1.2.1 Core Needle Biopsy
Core needle biopsy is the preferred method for obtaining tissue samples in NPM. It provides sufficient tissue for accurate pathological diagnosis and is less invasive than surgical biopsy. This method is supported by Level I evidence and Strength of Recommendation A.
1.2.2 Vacuum-Assisted Breast Biopsy
Vacuum-assisted breast biopsy may be considered in certain cases, particularly for larger lesions or when core needle biopsy is inconclusive. This method is assigned Level II evidence and Strength of Recommendation B.
Pharmacotherapy for Non-Puerperal Mastitis
The guidelines provide detailed recommendations for the pharmacological management of NPM, tailored to the specific pathological type and clinical presentation.
2.1 Granulomatous Lobular Mastitis (GLM)
2.1.1 Corticosteroids
Corticosteroids are the mainstay of treatment for GLM. Prednisone or methylprednisolone is commonly used, with a recommended dosage of prednisone 0.75 mg/kg/day for a 2-week course. The dose should be gradually reduced once symptoms resolve. Retrospective studies have shown that oral steroid therapy is effective in 72% to 86% of cases, with low recurrence rates. This treatment is supported by Level III evidence and Strength of Recommendation B.
2.2 Periductal Mastitis (PDM)
2.2.1 Anti-Infective Treatment During Acute Inflammation
Broad-spectrum antibiotics are recommended for managing acute inflammation in PDM. However, antibiotic treatment alone is not curative and should be combined with other interventions. This approach is supported by Level II evidence and Strength of Recommendation A.
2.2.2 Anti-Mycobacterial Drugs for PDM with Fistula Formation or Ulceration
In cases of PDM with fistula formation or ulceration, anti-mycobacterial therapy may be necessary. A combination of isoniazid (300 mg/day), rifampicin (450 mg/day), ethambutol (750 mg/day), or pyrazinamide (750 mg/day) is recommended for 9 to 12 months. This treatment is supported by Level III evidence and Strength of Recommendation B.
Surgical Interventions for Non-Puerperal Mastitis
Surgical treatment is often required for managing abscesses, sinuses, and fistulas associated with NPM. The guidelines provide specific recommendations based on the clinical presentation and severity of the condition.
3.1 Abscess
3.1.1 Incision and Drainage
Incision and drainage is the standard treatment for breast abscesses, particularly for larger or multiloculated abscesses. This method is supported by Level I evidence and Strength of Recommendation A.
3.1.2 Needle Aspiration with Ultrasound Guidance
For unilocular abscesses smaller than 3 cm, ultrasound-guided needle aspiration may be considered as a less invasive alternative to surgical drainage. This method is supported by Level II evidence and Strength of Recommendation A.
3.2 Sinus and Fistula
3.2.1 Fistulectomy
Fistulectomy is recommended for the management of persistent sinuses or fistulas in NPM. This surgical procedure involves the complete removal of the fistula tract and is supported by Level III evidence and Strength of Recommendation B.
Discussion and Expert Recommendations
The causes of NPM remain unclear, and there is a lack of high-level evidence to guide its diagnosis and treatment. The CSBrS guidelines are based on a combination of retrospective studies and expert consensus, providing a practical framework for clinicians. The following key points are emphasized:
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Comprehensive Assessment: A thorough clinical evaluation, including imaging and pathological examination, is essential for diagnosing NPM. Breast ultrasound is the preferred imaging modality, while core needle biopsy is the optimal method for obtaining tissue samples.
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Tailored Treatment: The treatment approach should be tailored to the specific pathological type and clinical presentation of NPM. Corticosteroids are the first-line treatment for GLM, while anti-infective and anti-mycobacterial therapies are recommended for PDM.
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Surgical Timing and Techniques: Surgical interventions, such as incision and drainage or fistulectomy, should be timed appropriately based on the clinical stage of the disease. Ultrasound-guided needle aspiration is a less invasive option for small abscesses.
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Avoiding Mastectomy: The decision to perform a mastectomy should be made with caution, as it is a radical procedure with significant implications for the patient.
The guidelines also highlight the need for further research to better understand the etiology of NPM and to develop more effective treatment strategies. Until then, the recommendations provided by the CSBrS serve as a valuable resource for breast disease specialists in managing this challenging condition.
DOI: 10.1097/CM9.0000000000001532
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