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Cystic neutrophilic granulomatous mastitis: an underappreciated pattern strongly associated with gram-positive

Andrew A Renshaw1, Robert P Derhagopian, Edwin W Gould

  • 1Dept of Pathology, Baptist Hospital, Miami, FL 33176, USA.

American Journal of Clinical Pathology
|August 18, 2011
PubMed

Insights

Granulomatous mastitis can be caused by gram-positive bacilli, though this is uncommon. Diagnosis requires careful histological examination for these bacteria within cystic spaces, leading to effective treatment.

Area of Science:

  • Pathology
  • Microbiology
  • Oncology

Background:

  • Granulomatous lobular mastitis (GLM) is an inflammatory breast condition.
  • While often idiopathic, associations with microorganisms are being explored.

Observation:

  • This study presents three cases of mastitis attributed to gram-positive bacilli.
  • Histological examination revealed suppurative abscesses with enlarged cystic spaces harboring rare gram-positive bacilli.
  • Two of the three cases also exhibited granulomatous inflammation.

Findings:

  • Despite negative cultures in all cases, the presence of gram-positive bacilli was confirmed microscopically.
  • A distinct histological pattern, characterized by cystic spaces within neutrophilic/granulomatous inflammation, was identified.
  • The identified pattern should prompt a targeted search for gram-positive bacilli within enlarged vacuoles.

Implications:

  • Gram-positive bacilli represent an under-recognized cause of mastitis with specific histological features.
  • Recognition of this pattern aids in diagnosis when cultures are negative.
  • Successful treatment involved biopsy and tetracycline-based therapy, suggesting targeted antimicrobial approaches.

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