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NCT Number: NCT07422870

GRAnulomatous MAstitis REGistry Study

Idiopathic granulomatous mastitis (IGM) is a rare benign inflammatory breast condition with unknown cause, affecting approximately 2.4 per 100,000 women aged 20-40 years. Patients experience severe local symptoms including pain, redness, and recurrent abscesses that can last weeks to months and often mimic inflammatory breast cancer. Due to its rarity, mostly case reports and case series exist in the literature, leading to limited knowledge about risk factors, optimal treatment strategies, and clinical outcomes.

The GRAMAREG study is the first European registry for patients with histologically confirmed idiopathic granulomatous mastitis. This retrospective/prospective observational cohort study aims to systematically evaluate the incidence, diagnostic features, clinical course, treatment strategies, and patient outcomes of this uncommon disease. The study collects both retrospective data (from January 1, 2015 onwards) and prospective data from participating sites across Europe.

All diagnostic and therapeutic procedures are conducted according to institutional standards in clinical routine, as this is a non-interventional study. Patients in the prospective cohort are followed for up to 5 years to document symptom duration and recurrence rates.

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Key information

Conditions

Idiopathic Granulomatous Mastitis Breast Diseases Congenital, Hereditary, and Neonatal Diseases and Abnormalities Cystic Fibrosis Digestive System Diseases Female Urogenital Diseases and Pregnancy Complications Genetic Diseases, Inborn Granulomatous Mastitis Infant, Newborn, Diseases Lung Diseases Mastitis Pancreatic Diseases Pregnancy Complications Puerperal Disorders Respiratory Tract Diseases Skin Diseases Skin and Connective Tissue Diseases Urogenital Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

University Hospital Düsseldorf, Düsseldorf, North Rhine-Westphalia, Germany

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About this study

Background:

Idiopathic granulomatous mastitis was first described by Kessler and Wolloch in 1972. The etiology remains largely unknown due to its rare occurrence. Valid prevalence data in Europe are lacking, though incidence appears higher in low-income countries compared to Western Europe. IGM predominantly occurs in women of childbearing age, mostly parous and more frequently of non-white ethnicity.

The diagnosis is confirmed only by histological evaluation, typically using core needle biopsy. Patients commonly develop recurrent breast abscesses that do not improve with antibacterial medication and often require repeat incisions or drainages. IGM must be differentiated from granulomatous inflammation associated with duct ectasia, foreign material reactions, specific infections (tuberculosis, fungi, parasites), systemic granulomatous diseases (sarcoidosis), and cystic neutrophilic granulomatous mastitis (CNGM) linked to Corynebacterium species.

Treatment strategies described in literature include high-dose steroids, immunosuppressive agents, bromocriptine, antibiotics, surgical resection, or even mastectomy. However, no evidence-based treatment recommendations are currently available.

Study Design:

This is an investigator-initiated non-interventional observational international prospective/retrospective cohort study with unlimited accrual and open registry duration due to disease rarity.

Data Collection Methods:

Retrospective Phase:

Collection and analysis via anonymized electronic database maintained by EUBREAST e.V. Participating Study Sites identify and document patients with histologically confirmed IGM treated between January 1, 2015, and Study Site activation. No patient identifying information is disclosed or documented. Data are fully anonymous without prospective follow-up.

Prospective Phase:

Patients with histologically confirmed IGM presenting after Study Site activation are informed about possible participation. Written informed consent is obtained. Diagnostic management and treatment follow institutional standards without protocol deviation. Follow-up occurs at 1, 3, and 5 years after first diagnosis to evaluate current symptoms and document potential recurrence.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Histologically confirmed idiopathic granulomatous mastitis OR cystic neutrophilic granulomatous mastitis by local pathology (minimally invasive biopsy or histological confirmation on surgical specimen)
  • First histological confirmation after January 1, 2015
  • Female or male patients ≥18 years old
  • Signed informed consent form for all patients included in prospective part of the study (patients presenting with idiopathic granulomatous mastitis after activation of the study at Study Site)

Exclusion criteria

  • Patients with suspicion of idiopathic granulomatous mastitis but without histological confirmation
  • Suspicion of OR confirmed secondary granulomatous mastitis due to:
  • Tuberculosis, Sarcoidosis, Fungal infection, Parasitic infection, Foreign body reaction

Treatment and study plan

Primary outcomes

  1. Proportion of Patients Presenting with Specific Symptoms

    Time frame: At initial diagnosis (baseline)

    Percentage of patients presenting with specific clinical symptoms including pain, redness, and palpable breast mass at initial presentation

  2. Duration of Symptoms Depending on Treatment Strategy

    Time frame: From initial diagnosis through symptom resolution, up to 5 years

    Time from initial symptom onset to symptom resolution measured in weeks or months, stratified by treatment approach (systemic treatment, surgical intervention, conservative management)

Secondary outcomes

  1. Type and Duration of Systemic Treatment

    Time frame: From initial diagnosis through completion of treatment, up to 5 years

    Specific systemic treatments received (e.g., corticosteroids, immunosuppressive agents, antibiotics) and duration of each treatment in weeks or months

  2. Number of Surgeries Performed

    Time frame: From initial diagnosis through 5 years follow-up

    Total number of surgical procedures (incision, drainage, excision, mastectomy) required per patient

  3. Recurrence Rate

    Time frame: At 1, 3, and 5 years after first diagnosis

    Proportion of patients experiencing recurrence of idiopathic granulomatous mastitis after initial treatment

  4. Risk Factors Associated with Recurrence

    Time frame: At 1, 3, and 5 years follow-up

    Identification of patient demographics, clinical characteristics, and treatment factors associated with disease recurrence

  5. Time to Histological Confirmation

    Time frame: At baseline (from retrospective chart review or patient recall)

    Time interval in days or weeks between first symptom occurrence and first histological confirmation of idiopathic granulomatous mastitis

  6. Presentation on Breast Imaging

    Time frame: At initial diagnosis

    Imaging characteristics on mammography, sonography, and MRI (if performed) as assessed by the International Steering Committee

Study contacts

Contact information is provided by the study sponsor or research team.

Natalia Krawczyk, PD Dr. med.

CONTACT

[email protected]

+49 0211 0

Sponsors and collaborators

Lead sponsor

European Breast Cancer Research Association of Surgical Trialists

Network

Registry information

Official study title

A Retrospective / Prospective Cohort Study to Evaluate the Incidence, Diagnostic Features, Clinical Course and Treatment Strategies in Histologically Confirmed Idiopathic Granulomatous Mastitis

Acronym: GRAMAREG

Important dates

Study start
2026
Primary completion
2031
Study completion
2036
First posted
Feb 20, 2026
Registry last updated
Feb 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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