Ultrasonographic Findings of Idiopathic Granulomatous Mastitis in a Case Series from a Tertiary Center

Idiopathic granulomatous mastitis (IGM) is one of the uncommon benign relapsing diseases of the breast and the imaging features of IGM can be indistinguishable from invasive or inflammatory breast carcinoma. Therefore, the assessment of the ultrasound features could be diagnostically helpful.

This retrospective research involved a total of 26 patients who had a final pathologic diagnosis of IGM and who underwent high-resolution ultrasound (US) and color Doppler evaluation.

Overall, 26 patients met the inclusion criteria. The age range of the patients was between 24 and 52 years old with an average of 34.81. About half of the patients (53.8%) reported pain as a presenting symptom and the most common physical finding was a palpable mass in 53.8% of the cases. Ultrasonography revealed the most common mass shape to be oval and irregular both with a frequency of 47.1%. Mass margins were mostly indistinct (70.6%) while angular and circumscribed margins were also seen. Heterogeneous echogenicity was observed in 71.4%, increased echogenicity of perilesional fat in 84.6%, posterior acoustic enhancement in 57.7%, peripheral vascularity in 30.8%, and subcutaneous collections in 19% of the patients., Internal vascularity was seen in 7% of the cases.

In the US of IGM, increased echogenicity of subcutaneous and perilesional fat were a common ultrasound feature (84.6%) while perilesional fat edema has not been mentioned in previous studies. In this study, other ultrasound features of IGM such as tubular extension, subcutaneous collection, indeterminate irregular masses, and collections were observed. They may contribute to the diagnosis of granulomatous mastitis in a proper clinical setting.