Imaging features of granulomatous mastitis in 36 patients with new sonographic signs

Idiopathic granulomatous mastitis is a rare relapsing benign inflammatory breast disease with unknown etiology. Its clinical features and imaging signs may mimic inflammatory breast cancer or some other inflammatory breast disease. This may interfere with correct and timely diagnosis and thus impose an additional burden on the costs of diagnosis and therapy, as well as patient anxiety. We aimed to characterize the imaging findings of this disease and introduce two new imaging signs.

This prospective study examined 36 patients with imaging and a clinical diagnosis of mastitis granulomatosis who were untreated and then confirmed by pathology. Demographic information, clinical data, imaging findings, and signs were recorded.

The age range of the patients was 22-60 years with an average of 36 years. Most of the patients (78%) were at reproductive age. None of the patients had a family history of granulomatous mastitis. Most patients with granulomatous mastitis (89%) lived in regions with low socioeconomic status. For most patients, sonography indicated a heterogeneous hypoechoic mass with irregular shape and ill-defined margin (26 cases; 72.2%). Focal asymmetry (36%) and obscured mass (36%) were the most common mammographic findings. Two signs of duct ectasia containing secretion and high-flow pseudocyst appearance were described.

Mammographic and ultrasound findings can highly suggest a diagnosis of granulomatous mastitis in an appropriate clinical context.