Ultrasonography-based staging of inflammatory granulomatous mastitis and estimation of steroid response

The aim of this study is to present novel diagnostic ultrasonography (USG)-based classification of inflammatory granulomatous mastitis (IGM) and to assess and compare dosage responses of locoregional steroid therapy.

From January 2017 through March 2023, total of 230 biopsy-proven IGM patients were reclassified (grades I, II, and III) according to USG-based morphological features. The injection applications were grouped in Group1 (40 mg/mL between years 2017 and 2019) versus Group2 (80 mg/mL between years 2019 and 2023), and effectiveness was analysed for each grade in between groups.

The mean age was 31 years old (range: 19-60) with median follow-up period of 7 months. The most common clinical presentation was breast mass accompanying draining skin sinuses of the affected skin and hypoechogenic mass with tubular extensions was the most prevalent feature on USG examination. As per USG-based features, 79 (34.3%) patients were redefined as grade I, 64 (27.8%) as grade II, and 87 (37.8%) as grade III. All patients underwent locoregional steroid injection only. The average number of treatments in the first group was 6 (±3 SD) with an effective dose of 40 mg/mL in the first group, and 4 (±2 SD) with an effective dose of 80 mg/mL in the second group. The generalized linear mixed model was used to investigate effects between groups (P < .05).

High-dose steroid treatment was effective in burnout lesions (grades II and III), and it was found to be statistically significant in lowering number of treatments irrespective of grade.

This novel classification could be a convenient tool in terms of common language between radiologists and clinicians. In addition, our study is a pioneer in comparing steroid dosage with no relapse in IGM patients.