Cystic Neutrophilic Granulomatous Mastitis: Association With Gram-Positive Bacilli and Corynebacterium

Am J Clin Pathol. 2016 May;145(5):635-45. doi: 10.1093/ajcp/aqw046.


Objectives: To determine whether cystic neutrophilic granulomatous mastitis (CNGM) can be associated with Gram-positive bacilli and Corynebacterium

Methods: We reviewed our experience with 35 granulomatous mastitis patients over a 10-year period, including histologic pattern, Gram stain and other microbiologic data, clinical presentation, treatment and outcome.

Results: Biopsies from 19 patients demonstrated CNGM, while 16 patients had other patterns of granulomatous mastitis. Gram-positive organisms were seen within microcystic spaces in 16/19 CNGM, but 0/16 non-CNGM patients (P = .000). Culture or molecular studies demonstrated Corynebacterium species in three, all CNGM. Patients with CNGM were more likely to be younger, of Hispanic ethnicity, and born outside of the United States. Granulomatous mastitis resolved after a protracted course with widely variable treatment (antibiotics, surgery, steroids).

Conclusions: Our data further support CNGM as an infectious disease; further study of Corynebacterium-directed therapy in CNGM is needed.

Keywords: Corynebacterium; Cystic neutrophilic granulomatous mastitis; Gram-positive rods; Granulomatous mastitis; IgG4.

MeSH terms

  • Adult
  • Aged
  • Corynebacterium Infections / complications*
  • Female
  • Gram-Positive Bacterial Infections / complications
  • Granulomatous Mastitis / microbiology*
  • Granulomatous Mastitis / pathology*
  • Humans
  • Middle Aged
  • Young Adult