Breast nonmalignant
Inflammatory
Cystic neutrophilic granulomatous mastitis

Deputy Editor: Debra Zynger, M.D.
Nat Pernick, M.D.

Topic Completed: 26 August 2018

Revised: 30 May 2019

Copyright: 2019, PathologyOutlines.com, Inc.

PubMed Search: Cystic neutrophilic granulomatous mastitis

Nat Pernick, M.D.
Page views in 2018: 1,116
Page views in 2019 to date: 2,705
Cite this page: Pernick N Cystic neutrophilic granulomatous mastitis . PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/breastcysticgranulomatousmastitis.html. Accessed August 18th, 2019.
Definition / general
Epidemiology
  • Rare
  • Most common in parous women
  • Median age 34 years (range 25 to 49 years)
Clinical features
  • Palpable breast mass
Diagnosis
Case reports
Treatment
Microscopic (histologic) description
  • Lobulocentric granulomas with mixed inflammation and clear vacuoles lined by neutrophils within granulomas
  • Gram positive bacilli are identified in about half of cases within microcystic spaces (Am J Clin Pathol 2016;145:635)
Microscopic (histologic) images

Images contributed by Ankur Sangoi, M.D.

Case of the Week #462, H&E

Case of the Week #462, Gram stain

Negative stains
  • Gram stain for gram positive bacilli (Corynebacterium)
Differential diagnosis
Board review question #1
Which of the following statements is true:

A. Cystic neutrophilic granulomatous mastitis only rarely is painful.
B. Gram positive bacilli are identified in >75% of cases.
C. Diagnosis may require matrix assisted laser desorption ionization–time of flight mass spectrometry.
D. Resolution typically takes days.
Board review answer #1
C. Diagnosis may require culture, 16S rRNA gene sequencing or matrix assisted laser desorption ionization–time of flight mass spectrometry.
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