Abstract

BACKGROUND
Granulomatous mastitis (GM) is a rare chronic inflammatory condition that clinically mimics a carcinoma. The diagnosis of idiopathic GM depends on the exclusion of other granulomatous inflammations. The purpose of this study is to correlate the clinicopathological features of GM with etiologies.
METHODS
We reviewed the clinical records of 58 cases that were histologically diagnosed as GM. We performed special stains for microorganisms such as Ziehl-Neelsen, periodic acid Schiff and gram stains, and polymerase chain reaction (PCR) for Mycobacterium tuberculosis (TB PCR).
RESULTS
The mean age of patients was 35.3 years. Most patients were parous except three. Seven patients (12.1%) were related with pregnancy or lactation. TB PCR was positive in nine patients (15.5%). Five patients (8.6%) had gram positive bacilli that were recognizable as coryneform bacteria. Culture study demonstrated Staphylococcus aureus in only one case. Infectious GM had a greater tendency to form abscesses. Fat necrosis was more likely to be present in idiopathic GM, but other histological features were similar to each other. Twenty-two cases (37.9%) showed recurrence.
CONCLUSIONS
We suggest that TB PCR and gram stain are essential tests for the differential diagnosis of GM, because the histologic features considerably overlap irrespective of the various etiologies.

• Keywords: Granuloma;Mastitis;Tuberculosis;Corynebacterium;Polymerase chain reaction