Ultrasonography in granulomatous mastitis: diagnostic differentiation, treatment response, and prognostic value

This study aimed to evaluate the diagnostic value of ultrasonography in distinguishing granulomatous mastitis (GM) from ductal carcinoma in situ (DCIS), and to assess its prognostic relevance in monitoring treatment response and predicting recurrence.

In this retrospective study, we analyzed conventional B-mode ultrasound and contrast-enhanced ultrasound (CEUS) features in 146 patients with histologically confirmed GM and 140 with DCIS. Key comparisons included: (1) B-mode characteristics (lesion morphology, posterior acoustic features, microcalcifications, vascular patterns, etc.); (2) CEUS quantitative parameters [mean transit time (mTTI), time to peak, rise time, etc.]. Clinical treatment responses and recurrence data were also collected for GM patients.

GM exhibited distinct ultrasound characteristics compared to DCIS, including more frequent posterior acoustic enhancement (58.90% vs. 12.14%), absence of microcalcifications (82.19% vs. 49.29%), and a higher prevalence of marginal or mixed vascular patterns (83.02% vs. 73.34%) (all P < 0.001). On CEUS, GM demonstrated shorter mTTI but higher peak enhancement, wash-in, and wash-out rates than DCIS (all P < 0.001). Among the GM cohort, 121 of 146 patients achieved clinical cure. These cured patients had significantly lower pretreatment mTTI values (P < 0.001), and mTTI demonstrated predictive value for treatment response (area under the ROC curve = 0.765; sensitivity: 68.0%, specificity: 86.0%). During one-year follow-up, 15 of the 121 cured patients experienced recurrence (12.40%). The presence of ductal dilatation on ultrasound was associated with a higher recurrence rate.

Ultrasound, particularly when combined with CEUS parameters, not only facilitates the differentiation of GM from DCIS but also serves as a valuable tool for evaluating treatment response and predicting recurrence in GM patients.